550: No such user here is a common error reported by cPanel users who primarily use an external mail server (like a corporate MX) to store their mail. Such users can include those who are trying to setup a mail forward to an external MX, those who recently migrated their accounts, or those who made recent changes to their account.
550: No such user here can be caused by issues ranging from improper file permissions to RFC non-compliance. The following are the few of the common causes for email error 550.
Email account doesn't exist or cannot be detected
When a user tries to send a mail through the server, the sending mail address needs to be present and active in the server. In recently migrated domains, it is possible that the email accounts might not be setup in the server. The customer would try to connect using the old email username, but the server would return an error as it cannot find a matching account. Such situations are quickly fixed by creating the corresponding email accounts.
In cPanel servers it is also possible that the mail configuration files have incorrect access permissions. This prevents the server from confirming the existence of an account, and results in an error. Such issues are quickly fixed by correcting the file and folder permissions of the account.
Duplicate sender account in recipient server
Sometimes it is possible that a user is unable to send mails to domains with his old service provider, or to another server within our network. For example, domainONE.com and domainTWO.com used to be with the same provider. domainONE.com migrated in to our servers, but is now unable to send mails to domainTWO.com. This happens because the name servers of domainTWO.com would still have entries of domainONE.com.
In such situations, the recipient server's administrators need to be contacted to get the phantom account deleted from their servers. In case, the recipient server is in our network, the duplicate account is deleted from that server.
Mis-configured mail exchanger
Some domains would have external mail servers like Google Apps, but webmasters would not have enabled remote MX routing for those domains. To confirm this, we check the MX of the domain, and if it is not pointing to us, we enable "Remote Mail Exchanger" under cPanel >> Mail >> MX Entry >> Domain >> Email Routing.
550 email is one of the common mail issues reported by cPanel users. Bobcares helps cPanel webmasters quickly resolve email errors, thereby minimizing business downtime.
