I know a lot of you guys are running your own VPSs so hopefully someone here knows what the issue I'm having is. I have a VPS on Digital Ocean and running a fresh Ubuntu LAMP installation. I used these three tutorials to setup an email server with Postfix, Dovecot, ViMbAdmin, RoundCube: https://rtcamp.com/tutorials/mail/server/postfix-dovecot-ubuntu/ https://github.com/opensolutions/ViMbAdmin/wiki/Installation https://rtcamp.com/tutorials/mail/fqdn-reverse-dns-ptr-mx-record-checks/ I went through the tutorials mostly without problems and everything seems to be working properly. I can login to ViMbAdmin and created a test email account for my domain which I can login to with RoundCube. However the problem I am having is that I cannot login to the same email account with Thunderbird and I cannot sucessfully send or receive emails through RoundCube. Does anyone have any idea what things I could check that might be causing me problems?