Seems I spoke too soon, unless this is another issue. MySQL service seemed to stop running (Wordpress sites failed to connect to database). I couldn't connect to Webmin either so I thought I would do a reboot. However the server didn't boot but got stuck on "fsck exited with status code 4". A quick Google showed me how to manually run fsck, which I did and after quite a few errors, the system started again but the wordpress sites again failed to connect to their databases. I logged in via PuTTY and ran "service mysql restart" and everything started working again. I could log into webmin again too. My question is what logs do I look into to see what may have caused the problem?
Webmin connection failure