If your email account is disconnected in Smartlead, you can easily reconnect it by following these steps:
Log in to your Smartlead account
Navigate to the Email Accounts tab. Select the account(s) you want to reconnect by checking the box next to them. You can select a single account, select this page (40), or select all accounts using the dropdown that appears
Once selected, click the Settings icon (gear icon) in the top right of the accounts table.
In the Advanced Settings panel that appears, click "(Re)connect Emails"
Your selected email accounts will now be reconnected.