I installed Postfix & Dovecot on Debian.
Then I tried using SMTP authentication according to this guide:
Unfortunately the following test tails:
telnet localhost 25 auth plain <base64 encoded usernaem/password>
We get a "535 5.78 Error: authentication failed:"
in var/log/mail.warn we habe a new line which is: "warning: localhost[127.0.0.1]: SASL PLAIN authentication failed:"
unfortunately it does not say what is wrong. Any ideas?