I've got a pretty general problem here, where users cannot login through usermin (eg. domain.com:20000) using the correct username/password - they're greeted every time with the 'Login failed. Please try again.' message.
However, if I'm logged in to Virtualmin and hit the 'Login to Usermin' button then I can access it just fine.
I've checked /var/usermin/miniserv.log and it just shows the session_login.cgi page being served, and I've checked /var/usermin/miniserv.error and there's nothing recorded at all.
Any clues where to start looking to fix this? Many thanks, Benjamin