Today my email server got this type of error, when I tail -f /var/log/maillog
Why? It’s seem that why every user keep trying to login their username? It it a bug or wrong configuration?
Feb 10 14:06:54 mws dbmail/imap4d[4110]: Message:[imapsession] dbmail-imapsession.c,dbmail_imap_session_handle_auth(+1623): user (id:10361, name badrulhisham) tries login
Feb 10 14:06:54 mws dbmail/imap4d[4110]: Message:[imapsession] dbmail-imapsession.c,dbmail_imap_session_handle_auth(+1644): user (id 10361, name badrulhisham) login accepted
Mail Servers generally can be configured to support credentials authenticated by a number of different providers… some examples might be
Local mail server application (credentials stored by the app, does its own authentication)
Local machine (mail server app passes the credentials to the local machine or authentication, usually the User Account is configured in a mail account group without local logon permissions)
Network (credentials are passed to a Network Authentication provider like a Domain Controller)
However your mail server app is configured, client apps should be configured accordingly.
Since you didn’t provide a detailed description of both server and client configurations, I can’t hazard a guess what is really going on but hopefully with this info you can evaluate what you observe.