Try to Send a Test Email
First you can try to send a test email to see if there’s still an error:
If you receive the test email, click “Retry Status Check:”
If You Do Not Receive Your Test Email
Click the status message for more information about the issue with the connected email:
Error Descriptions
If when you click, a modal window pops up showing an SMTP Error, see the following SMTP Errors for explanations and possible solutions
Error: SSL routines:ssl3_get_record:wrong version
What does it mean?
This often indicates that your SMTP server is using an outdate version of SSL encryption or is serving HTTP from the HTTPS port.
How can you fix it?
If you are currently trying to use port 587, you can try port 465. Update your connection details here. Then try to send a test email. If the test email still does not come in, talk to your SMTP server host.
450-Requested mail action not taken: mailbox unavailable
What does it mean?
A 450 email error can be a temporary issue with the receiving mail server and does not necessarily mean there is an underlying SMTP issue.
How can you fix it?
Try to send a test email. If the test email does not come in, contact support.
550 5.4.6: Recipient address rejected: Email Sending Quota Exceeded
What does it mean?
A 550 error is likely due to the recipient email having run out of space in their inbox.
How can you fix it?
Try to send a test email. If the test email does not come in, contact support.
Error: certificate has expired
What does it mean?
This is caused by an issue with your SMTP server’s SSL certificate.
How can you fix it?
Talk to your SMTP server host.
Error: Client network socket disconnected before secure TLS connection was established
What does it mean?
This is usually due to an issue with the proxy used by your SMTP server.
How can you fix it?
Talk to your SMTP server host.
Error: connect ECONNREFUSED [IP]:[Port]
What does it mean?
This is usually due to an issue with the proxy used by your SMTP server.
How can you fix it?
Talk to your SMTP server host.
Error: Connection timeout
What does it mean?
This typically means that the SMTP port is incorrect.
How can you fix it?
Try other SMTP ports: 587, 465, 25, 2525. Update your connection details here. Then try to send a test email. If the test email still does not come in, talk to your SMTP server host.
Error: Data command failed: 550 5.4.5 Daily user sending quota exceeded
What does it mean?
This typically means that the SMTP port is incorrect.
How can you fix it?
Try other SMTP ports: 587, 465, 25, 2525. Update your connection details here. Then try to send a test email. If the test email still does not come in, talk to your SMTP server host.
Error: Hostname/IP does not match certificate’s altnames
What does it mean?
This is an issue with the SMTP server’s SSL certificate signing.
How can you fix it?
Talk to your SMTP server host.
Error: Invalid login: 534-5.7.9 Application-specific password required.
What does it mean?
Your SMTP server requires App Passwords and does not accept your standard password for authentication.
How can you fix it?
Create an App Password with your email host, then update your connection details here, using the App Password in the password field.
Error: Invalid login: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Tenant
What does it mean?
Most often, this is an error from a Microsoft email where you have not enabled SMTP authentication.
How can you fix it?
- Open the Microsoft 365 admin center and go to Users > Active Users.
- Select the user
- In the flyout that appears, click Mail
- In the Email apps section, click Manage email apps
- Check the box next to Authenticated SMTP
- When you’re finished, click Save changes
Error: Invalid login: 535 5.7.3 Authentication unsuccessful
What does it mean?
This means that the SMTP server is rejecting the credentials used to authenticate.
How can you fix it?
If you are trying to connect a Microsoft email via the custom SMTP/IMAP rather than the Microsoft option in the setup that uses Oauth authentication, you will have to reconnect this email here.
Error: Invalid login: 535 5.7.8 Error: authentication failed
What does it mean?
This means that the SMTP server is rejecting the credentials used to authenticate.
How can you fix it?
Verify your username and password are correct and reconnect this email here.
Error: Invalid login: 535 Authentication Credentials Invalid
What does it mean?
This means that the SMTP server is rejecting the credentials used to authenticate.
How can you fix it?
Verify your username and password are correct and reconnect this email here.
Error: Invalid login: 535 Authentication Failed
What does it mean?
This means that the SMTP server is rejecting the credentials used to authenticate.
How can you fix it?
Verify your username and password are correct and reconnect this email here.
Error: Invalid login: 535-5.7.8 Username and Password not accepted
What does it mean?
This is most often an error given by a Gmail address when you haven’t used a App Password and are instead trying to use your regular login password.
How can you fix it?
Refer to this help doc for connecting gmail addresses with an App Password and then reconnect this email here.
Error: Timeout waiting for command response
What does it mean?
Your SMTP server is not responding.
How can you fix it?
Talk to your SMTP server host.
Message failed: 451 4.3.111 Temporary server error.
What does it mean?
Your SMTP server has a temporary error.
How can you fix it?
Wait a little while and then try to send a test email. If the test email is successful, click “Retry Status Check” (shown above) and your email will be reenabled.
454 4.7.0 Cannot authenticate due to temporary system problem. Try again later.
What does it mean?
Your SMTP server has a temporary authentication error.
How can you fix it?
Wait a little while and then try to send a test email. If the test email is successful, click “Retry Status Check” (shown above) and your email will be reenabled.
in Boston.