I crate a user named "testuser" on my linux server. I then go to the roundcube mail webpage, I canot log in as "testuser" or as "testuser@mydomain.com". If I putty to the Linux server, I can log in as "testuser" into the command line. Whatever is supposed to automatically create a roundcube mail user account in the database is not creating it.
This is a standalone Centos server so the user is being added by the "useradd" command on the command line. This is not CPANEL or any other type of Linux server. Everything in this forum seems to indicate that most people add users using CPANEL which may be doing something different than the generic useradd script.