Placement:
Inbox - Is the Aim
Tabs - All other folders other than Inbox, Junk and Junk
Spam Folder
Missing - Sent by Sender mailbox, but either not received by Seedlist or lost in transition. ****
Unmailable: Sender Mailbox Authentication Failed
Bounced Emails: Emails not received by seed list but instead sent back to the receiver
Potential Actions:
A. Missing Emails
If your campaign emails are not being received by the intended recipients, there are several potential causes related to technical issues, email reputation, content, or list quality. Here’s a breakdown of the most common reasons why your emails may not be reaching the recipient’s mailbox:
1. Poor Sender Reputation
Domain/IP Reputation: If your sending domain or IP address has a poor reputation, receiving mail servers may reject your emails or filter them as spam before they reach the inbox. Tools like Google Postmaster Tools, Microsoft SNDS, and Sender Score can help monitor your reputation.
Blacklist Issues: Your IP or domain might be listed on blocklists such as Spamhaus, SORBS, or Barracuda, leading to automatic rejection by email service providers (ESPs). Use MXToolbox to check if you're on any blacklists.
2. Email Authentication Failures
SPF Failure: If your SPF (Sender Policy Framework) record is not correctly set up or fails validation, receiving servers may reject your email. Make sure the SPF record aligns with the servers authorized to send on behalf of your domain.
DKIM Failure: Invalid or missing DKIM (DomainKeys Identified Mail) signatures may cause emails to be rejected or marked as spam. Ensure DKIM is set up correctly and the signature is valid.
DMARC Policy Issues: If you don’t have a DMARC (Domain-based Message Authentication, Reporting & Conformance) policy, receiving servers may reject your email as a security precaution. A DMARC policy helps instruct receiving servers on how to handle SPF and DKIM validation failures.
3. Emails Blocked by Spam Filters
Spam Triggers in Content: Certain words, phrases, or email elements can trigger spam filters, leading to your emails being flagged as spam or rejected outright. Avoid excessive use of words like “Free,” “Discount,” or "Limited Time Offer" and be mindful of suspicious formatting (e.g., all caps, multiple exclamation points).
High Image-to-Text Ratio: If your emails contain too many images relative to text, they may be seen as spam. Ensure a good balance between text and images.
Suspicious Links or Attachments: Emails containing suspicious links or attachments (especially large files or executable formats) can be blocked or filtered. Use clean, reputable links, and avoid attaching large or unnecessary files.
Overuse of HTML: Emails with complex HTML formatting or missing a plain-text version can trigger spam filters. Ensure you provide both HTML and plain-text versions of your emails.
4. Issues with the Email List
Invalid or Outdated Email Addresses: If you're sending to invalid or inactive email addresses, many emails may bounce back. Use email validation tools (e.g., ZeroBounce, NeverBounce) to clean your list before sending.
Spam Traps in Your List: If your email list contains spam traps (email addresses set up to catch spammers), emails will be rejected and your sender reputation will be impacted. Avoid using purchased lists or unverified data.
Poor List Hygiene: Continuously sending emails to unengaged or inactive users can lead to high bounce rates or spam complaints, leading to lower inbox placement. Segment your list and regularly remove inactive subscribers.
5. IP or Domain Blacklisting
Blacklisted IP: If the IP address from which you’re sending emails is blacklisted, the receiving mail server will block your emails. This can happen if the IP has a history of sending spam or receiving complaints.
Blacklisted Domain: Similarly, if your domain has been flagged for spammy behavior, your emails will be rejected or filtered as spam.
6. ISP-Specific Issues
Receiving Mail Server Policies: Some ISPs (e.g., Gmail, Outlook, Yahoo) have stricter policies for filtering and rejecting emails based on sender reputation, content, or sending volume. Check if your emails are being filtered differently by specific ISPs.
Rate Limiting: If you're sending too many emails too quickly, some ISPs may temporarily block or throttle your emails. Use proper email throttling to avoid overwhelming mail servers (e.g., limiting the number of emails sent per hour).
Greylisting: Some ISPs employ greylisting, where unknown senders are temporarily rejected. Legitimate emails are usually retried after a short delay, but not all mail servers handle this automatically.
7. Improper DNS Settings
rDNS (Reverse DNS) Issues: If your IP address lacks a reverse DNS entry or the rDNS doesn’t match your sending domain, receiving mail servers may reject your emails. Ensure you have proper rDNS setup for your sending IP.
MX Record Issues: Ensure your domain has valid MX (Mail Exchange) records to handle email routing. Incorrect MX records can lead to deliverability problems.
8. Content and Formatting Problems
Missing Plain-Text Version: If your email contains only HTML without a corresponding plain-text version, some mail servers may flag it as suspicious. Always include a plain-text alternative.
Non-Compliant Headers: Ensure your email headers, such as "From," "Reply-To," and "Message-ID," comply with RFC standards. Misconfigured or malformed headers can cause emails to be rejected.
9. High Bounce or Complaint Rates
Bounce Rate: A high bounce rate indicates you're sending to invalid or non-existent email addresses, which damages your sender reputation. Once your bounce rate exceeds a certain threshold, receiving mail servers may block your emails altogether.
Spam Complaints: If too many recipients mark your email as spam, your sender reputation will be affected. Once your reputation deteriorates, mail servers may reject your emails automatically.
10. Email Warm-Up Issues
New Domains or IPs: If you're using a new domain or IP to send emails, you need to warm them up gradually. Sending too many emails too quickly from a new domain or IP can result in deliverability issues as ISPs don’t yet trust your sending infrastructure.
Incomplete Warm-Up Process: Ensure that your domain and IP warm-up process is complete before sending large campaigns.
11. Message Size
Oversized Emails: If your email is too large (usually over 25 MB including attachments), it may be rejected by the recipient's server. Keep your email content and attachments small to avoid exceeding size limits.
12. Third-Party Blocklists
Third-Party Filtering: Some organizations use third-party spam filters or blocklists to protect their users. If your IP or domain is flagged by these third-party services, your emails may be blocked before they reach the recipient.
Steps to Fix and Improve Deliverability:
Check Blacklists: Use tools like MXToolbox to check if your IP or domain is blacklisted and request removal if necessary.
Authenticate Emails: Ensure your SPF, DKIM, and DMARC records are properly configured and working.
Warm Up Your Domain/IP: If you’re using new domains or IP addresses, warm them up by sending low volumes of emails at first and gradually increasing the volume.
Monitor Bounce Rates: Remove hard bounces from your list and use email validation services to clean your list.
Use Reputable Email Service Providers: Use a trusted email service provider (ESP) that ensures high deliverability and compliance with email authentication standards.
Monitor Spam Complaints: Regularly review feedback loops to identify and address any spam complaints or issues with your campaigns.
Optimize Content: Avoid spammy content, large attachments, or poorly formatted HTML emails that could trigger spam filters.
By addressing these factors, you can significantly improve the chances of your emails being delivered to the recipient's inbox.
B. Unmailable
If your emails are not leaving your mailbox or cannot be sent, several factors could be affecting the functionality of your sender mailboxes. These issues can arise due to problems with your email configuration, email service provider (ESP) limits, mailbox settings, or even network issues. Below are potential reasons for this and steps to improve your mailboxes to avoid such issues:
1. SMTP Configuration Issues
Incorrect SMTP Settings: The most common reason emails fail to send is incorrect SMTP configuration (Simple Mail Transfer Protocol). Make sure you have the correct SMTP server address, port number, and security settings (SSL/TLS) for your email service provider.
Solution: Double-check the SMTP settings for each mailbox. For example:
Gmail: smtp.gmail.com, Port 465 (SSL) or 587 (TLS).
Outlook: smtp.office365.com, Port 587 (TLS).
Amazon SES: Check the specific SMTP endpoint for your region.
Ensure the correct username (email address) and password are used, and any necessary API keys or credentials are properly configured.
2. Authentication Problems
Failed Authentication: If your SMTP authentication (username, password, or OAuth tokens) is incorrect or outdated, your email will fail to send.
Solution: Verify the login credentials for each email account. If using OAuth (e.g., Google or Microsoft accounts), ensure that OAuth tokens are valid and haven’t expired. If they have, you might need to reauthorize your account.
Two-Factor Authentication (2FA): Some providers require an app-specific password if 2FA is enabled.
Solution: Generate app-specific passwords for accounts that use 2FA.
3. Rate Limiting and Sending Limits
Exceeding Daily/Hourly Sending Limits: Many ESPs have limits on how many emails can be sent per day or per hour from an account. For example, Gmail limits free accounts to 500 emails/day, and even with Google Workspace, limits may vary depending on the plan.
Solution: Check with your ESP regarding sending limits. If you're hitting these limits, you may need to:
Use multiple mailboxes to distribute the sending volume.
Switch to an ESP that offers higher sending limits (e.g., Amazon SES, SendGrid, Mailgun).
Use proper rate limiting within your cold email platform to avoid exceeding these limits.
4. Spam or Abuse Detection by ESP
ESP Blocks Due to Suspicious Activity: If your sending behavior is flagged as suspicious by your email provider (e.g., sending too many emails in a short period or sending to low-quality lists), your account could be temporarily blocked from sending emails.
Solution: Avoid sending too many emails at once. Implement gradual email sending or "warm-up" strategies for new email accounts or IPs. Clean your email list regularly to avoid sending to invalid addresses.
5. Email Queue Backlogs
Overloaded Email Queue: If you're sending a large number of emails at once, the email server's queue may become overloaded, causing delays in sending or failure to send emails.
Solution: Implement email throttling and stagger email sends to prevent queue overload. Many email platforms and SMTP servers allow you to control the sending rate (e.g., limiting to X emails per minute/hour).
6. DNS Records and Email Authentication
Missing SPF/DKIM Records: If your domain lacks SPF, DKIM, or DMARC records, receiving servers may reject your emails or block your sending ability.
Solution: Ensure your domain’s DNS settings include valid SPF and DKIM records. Both are critical for email authentication and improving deliverability. Set up DMARC to handle emails that fail SPF or DKIM checks.
rDNS (Reverse DNS) Issues: Ensure that your IP address has a reverse DNS entry that resolves to your sending domain.
7. ISP or ESP Blocking Outbound Emails
Outbound Filtering by ISPs: Some internet service providers (ISPs) or email service providers block outbound email traffic from certain ports (e.g., Port 25). This is common in shared hosting environments or with certain ISPs.
Solution: Use the correct ports for secure email sending (usually Port 465 or 587 for SSL/TLS). If Port 25 is blocked, contact your hosting provider or ISP to ensure proper outbound email traffic.
8. Account Suspension or Restrictions
ESP Account Limits: Some providers will temporarily suspend or throttle your account if they detect unusual sending activity, high bounce rates, or complaints.
Solution: Check with your email provider to see if your account has been flagged or temporarily restricted. Ensure you're complying with their terms of service, and avoid sending large volumes of unsolicited emails.
9. Blacklist or Reputation Issues
IP or Domain Blacklisted: If your sending domain or IP address is blacklisted due to prior spam complaints or poor email practices, your emails will not be sent or will be rejected.
Solution: Use tools like MXToolbox or Spamhaus to check if your IP/domain is blacklisted. If you are listed, follow the de-listing procedures. Also, improve your sending practices to avoid future listings.
10. Security and Privacy Settings
Firewall or Security Settings Blocking SMTP Traffic: Some email clients or firewalls can block outgoing email traffic if improperly configured.
Solution: Check your firewall or security software settings to ensure they allow outbound SMTP traffic. Make sure the correct ports (usually 465 or 587) are open.
11. Mail Client Issues
Misconfigured Email Clients: If you're using email clients like Outlook, Thunderbird, or other desktop/mobile email apps, misconfigurations in those clients can prevent emails from being sent.
Solution: Ensure that your email client settings match your provider’s recommended configuration, including authentication methods, server settings, and encryption protocols.
12. SMTP Relays and Throttling
Insufficient SMTP Relays Available: Some email providers limit the number of SMTP relays (outgoing emails) available per day or per hour, especially for free accounts.
Solution: Upgrade to a higher-tier plan or switch to an SMTP service with higher sending limits (e.g., Amazon SES, SendGrid, etc.).
13. Attachment Size or Email Content Issues
Oversized Attachments: Emails with large attachments may fail to send due to size limitations imposed by the ESP or the recipient’s mail server.
Solution: Reduce the size of attachments, or use links to cloud storage services like Google Drive or Dropbox.
Suspicious Content: Emails with certain words, links, or attachments can trigger content filters, preventing them from being sent.
Solution: Avoid using spammy language, excessive images, or suspicious attachments.
How to Improve Mailboxes for Reliable Email Sending:
Use a Reputable ESP or SMTP Provider:
Consider using a dedicated SMTP provider such as Amazon SES, SendGrid, or Mailgun for reliable email sending. These services have higher limits and better infrastructure for handling bulk emails.
Warm Up Your IP and Domain:
Gradually increase the number of emails sent from a new domain or IP address. This "warming up" process builds a good sending reputation and avoids issues with deliverability.
Monitor Your Sender Reputation:
Use tools like Google Postmaster Tools, Microsoft SNDS, and Sender Score to monitor your IP and domain reputation and ensure you're not being flagged for spammy behavior.
Implement Proper Email Authentication:
Set up and configure SPF, DKIM, and DMARC to authenticate your emails and improve your chances of delivery.
Segment Your List and Maintain List Hygiene:
Regularly clean your email list by removing invalid, unengaged, or hard-bounced email addresses. This prevents sending to bad addresses and lowers the chance of triggering ESP filters.
Track and Fix Bounce Rates:
Use an email validation tool before sending a campaign to ensure all addresses are valid. Reduce bounce rates by sending to verified lists only.
Throttling Email Sends:
Use proper email throttling to prevent overwhelming servers and ensure a steady flow of emails, especially if sending large volumes.
By addressing these potential issues and implementing the above solutions, you can improve the reliability of your sender mailboxes and avoid problems with sending emails.
C. Bounced Emails
Bounced emails are messages that could not be delivered to the recipient’s email address and are returned to the sender by the recipient’s mail server. Bounced emails are typically categorised into two types:
1. Hard Bounces
Definition: A hard bounce indicates a permanent delivery failure. This means the email cannot be delivered for reasons that are unlikely to be resolved without intervention.
Causes of Hard Bounces:
The recipient’s email address is invalid (e.g., the domain no longer exists or the email address is misspelled).
The email address does not exist anymore.
The domain name is incorrect.
Action: Immediately remove hard-bounced email addresses from your list to maintain good deliverability and avoid damaging your sender reputation.
2. Soft Bounces
Definition: A soft bounce indicates a temporary delivery issue that may be resolved automatically. These types of bounces usually occur due to temporary problems on the recipient’s end.
Causes of Soft Bounces:
The recipient’s inbox is full (over quota).
The recipient’s mail server is temporarily unavailable or experiencing downtime.
The email message is too large for the recipient’s inbox.
Temporary DNS issues or filtering based on content.
Action: Monitor soft bounces closely. Some email service providers attempt to resend soft-bounced emails for a short period. If the issue persists, consider removing these addresses from your list.
Common Bounce Code Examples:
5xx Codes: These are permanent failures (hard bounces). Example: "550 - No such user here" (the email address doesn't exist).
4xx Codes: These are temporary failures (soft bounces). Example: "421 - Service temporarily unavailable" (the server is down temporarily).
Importance of Managing Bounces:
Impact on Sender Reputation: High bounce rates can harm your sender reputation and increase the likelihood of your emails being flagged as spam.
Deliverability Issues: If you continuously send to invalid or non-existent email addresses, your domain or IP could be blacklisted, causing further deliverability issues.
Actionable Data: Monitoring bounce rates helps you clean your email list, ensuring you're sending to valid, engaged recipients.
By regularly cleaning your email list and addressing bounces, you can improve your overall email deliverability and engagement.
How to reduce your bounce rates:
Reducing your email bounce rate is crucial to maintaining good sender reputation and improving your overall email deliverability. Here are some actionable steps to help you reduce your bounce rate:
1. Clean Your Email List Regularly
Use Email Verification Services: Before sending emails, use tools like ZeroBounce, NeverBounce, or BriteVerify to validate and clean your email list. These services can identify invalid, fake, or outdated email addresses.
Remove Hard Bounces Immediately: As soon as you notice hard bounces, remove those addresses from your list. Keeping them will negatively impact your reputation.
Segment Your List: Regularly segment your email list into active and inactive users. Send emails only to users who have engaged with your emails in the last 3-6 months to reduce bounce rates.
2. Use Double Opt-in for New Subscribers
What It Does: When someone signs up for your email list, send a confirmation email requiring them to verify their email address by clicking a link. This ensures you're only collecting valid and real email addresses.
Benefit: Double opt-in helps prevent fake, misspelled, or mistyped email addresses from entering your database, reducing the chance of bounces.
3. Check and Fix DNS Settings
SPF, DKIM, and DMARC: Ensure that you have properly configured SPF, DKIM, and DMARC records for your domain. These authentication measures help email servers verify that your emails are legitimate, reducing the risk of being marked as spam or bouncing due to authentication failures.
rDNS: Set up reverse DNS (rDNS) for your sending IP address. This allows receiving servers to verify where the email came from, further reducing the chance of rejection or bouncing.
4. Warm Up Your Domain and IP
Start Slowly: If you're using a new domain or IP address, start sending a small number of emails and gradually increase the volume. This process, called domain and IP warming, helps build a positive sender reputation over time.
Monitor Performance: As you increase the volume, monitor the performance of your emails. If bounce rates increase, slow down and address any issues before scaling up.
5. Avoid Sending to Inactive Email Addresses
Monitor Engagement: Track open rates and clicks to identify inactive subscribers who haven’t engaged with your emails for a long time. Consider sending a re-engagement campaign to win them back or remove them from your list if they remain inactive.
Use Engagement-Based Lists: Focus your email campaigns on users who have recently interacted with your emails to reduce the chances of bounces.
6. Avoid Spam Traps
Purchased Lists: Never use purchased, rented, or scraped email lists. These lists often contain spam traps, fake emails, and outdated addresses that will result in high bounce rates.
List Hygiene: Regularly clean your list, even if it's organic. Use email verification tools to identify risky addresses, such as role-based emails (info@, support@) or generic inboxes that could increase bounces.
7. Monitor Email Content and Size
Avoid Large Attachments: Some email servers reject emails that exceed a certain size. Keep attachments and overall email size to a minimum.
Watch Content Filters: Avoid using spammy words or overusing links, images, and exclamation points in your emails. Emails flagged as spam by content filters are more likely to bounce.
8. Use a Reliable Email Service Provider (ESP)
Choose an ESP with Good Reputation: Using reputable ESPs like Amazon SES, SendGrid, or Mailgun can help ensure better deliverability since they manage IP reputation and authentication protocols effectively.
Monitor ESP Health: Regularly monitor your ESP's IP and domain reputation. If their IPs are blacklisted or their deliverability is low, consider switching providers.
9. Monitor Blocklists
Check Your Domain and IP: Regularly check if your sending domain or IP address is listed on blocklists like Spamhaus or MXToolbox. Being listed on a blocklist can cause bounces.
Remove Blocklist Listings: If your domain or IP is listed, follow the blocklist removal process provided by the relevant authority.
10. Use Engagement Filters
Remove Unengaged Users: If a user hasn’t opened or interacted with your emails over a significant period, consider removing them from your list. Sending to unengaged users can lead to bounces or spam complaints.
11. Keep Your Email Format Simple
Plain Text vs. HTML: Consider sending emails with a simple format, such as plain text with minimal images and links. HTML-heavy emails or overly complex designs can trigger spam filters, leading to bounces.
Provide Text and HTML Versions: Always send a plain-text version of your email alongside the HTML version to ensure proper rendering and reduce the chances of bounces.
12. Monitor and Analyze Bounce Reports
Review Bounce Codes: Every time an email bounces, the receiving server sends a bounce code (e.g., 4xx for soft bounces, 5xx for hard bounces). Analyze these codes to understand why your emails are bouncing and take corrective action.
Adjust Your Strategy: If you see patterns in bounce reports (e.g., specific ISPs rejecting your emails), adjust your sending patterns or contact the ISP for assistance.
By following these best practices, you can significantly reduce your bounce rates and improve overall deliverability, ensuring that more of your emails reach the inbox.