Error Message<[xx.xx.xx.xx] #5.0.0 smtp; 5.1.0 - Unknown address error 550-'Verification failed for <[email protected]>
The mail server could not deliver mail to [email protected]. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries. Sender verify failed' (delivery attempts: 0)
SolutionThe mail is getting rejected because recipient mail server has enabled sender verification callouts. That means, before delivering emails to the recipient, existence of email address is verified by recipient mail server. If sender email address does not exist on the sender's server, the email is rejected.
If your email server is also rejecting emails due to the above reason, you can disable the following settings from the WHM. Following are the steps:
Go to the WHM -> Exim configuration editor -> set sender verification callouts =Off.