I had setup an ISPConfig system with Roundcube on Ubuntu 20.04 hosted with AWS EC2. The setup was all fine, logged in into Roundcube and tried to send a mail. There was the problem – Roundcube says Error 250: Authentication failed. It seems others also faced the same issue and different solutions worked for different… Continue reading Outgoing email problem with Roundcube, ISPConfig 3.2 and Ubuntu 20.04 on AWS