When attempting to access Webmail, the page redirects to the login page. The following errors will appear in the cPanel login_log file: ( /usr/local/cpanel/logs/login_log )
"POST /login/?login_only=1 HTTP/1.1" FAILED LOGIN webmaild: user password
hash is missing from system (user probably does not exist)
cPanel error logs also return similar errors: ( /usr/local/cpanel/logs/error_log )
Cpanel::Exception::DomainDoesNotExist/(XID pje7hu) The domain “domain.com”
does not exist. at /usr/local/cpanel/Cpanel/AcctUtils/Lookup.pm line 63.
If the hostname domain uses the same domain as an account domain, it will cause account domain lookup failures. The cPanel software doesn't support setting the same hostname for an account domain being hosted. It is best to ensure the hostname is defined according to cPanel hostname requirements.
Change the hostname. You can find additional details for setting effective hostnames in the article below.
After setting the hostname update the user domains to finalize the change.