Comment 2 for bug 879460

Hy krypto_est, thanks for taking the time to file this bug report.

Error code 75 is usually caused by an invalid hostname which postfix rejects. Check /etc/hostname and /etc/mailname and make sure they are valid internet hostnames, no puncutuation except -'s and .'s, and that they only begin with letters.

(side note, there is code in 11.10's postfix package to help user's identify this problem before reporting it as a bug, I assume that this wasn't triggered because it happened during upgrade, before said code had been put in place by apport).