If you are not able to access email even with correct username and password and you see below error in the /var/log/maillog
Jul 5 18:15:20 hostname dovecot: auth: Error: Cpanel::MailAuth: Failed to getpwnam for user webmaster Jul 5 18:15:38 hostname dovecot: auth: Error: Cpanel::MailAuth: Login not permitted to account with a uid lower then 500 (498) Jul 5 18:15:56 hostname dovecot: auth: Error: Cpanel::MailAuth: Failed to getpwnam for user admin Jul 5 18:54:38 hostname dovecot: auth: Error: Cpanel::MailAuth: Failed to getpwnam for user info Jul 5 18:54:45 hostname dovecot: auth: Error: Cpanel::MailAuth: Failed to getpwnam for user info Jul 5 18:55:06 hostname dovecot: auth: Error: Cpanel::MailAuth: Failed to getpwnam for user info
Reason:
This happens if hostname is same as domain. The mail server will try to authenticate against system user of the server instead of virtual domains on the server.
Solution:
Change the hostname of the server to something else other than domain name. e.g. if your domain is domain.com then you can set the hostname as host.domain.com
Also make sure that there is entry of the domain in both /etc/localdomains and /etc/userdomains.
