I'm facing a strange problem and I am in hope someone can give me a hint on this. ISPConfig 188.8.131.52 on Debian. Everything but mailing seems to work. I've set up domains, mailboxes etc and set up a mail client to senc/receive over imap. When I try to send a mail from an accoutn configured in ispconfig to itself, it works. But when I want to send a mail to my private gmail address I don't receive anything there. Sending from gmail to my ispconfig defined mailbox works, though. I don't get any log entries in mail.log, mail.err, mail.warn, mail.info or my custom dovecot debug log when sending a mail.