Had configured my Zimbra MTA to use TLS. When using a new email client on my Windowsphone 8 operating system (yeah yeah, it’s my mobile for my job, I didn’t chose it myself) I was not able to send email via TLS and accepting self-signed-certificates. So… I had to disable TLS authentication only to be able to send email again from this client from an external network.
- Adjust the setting in the admin webinterface: Configure > Servers > Select server > MTA > uncheck “TLS authentication only”.
- su – zimbra
- postfix reload
Errors in the maillog (tail -f /var/log/maillog):
Feb 28 21:08:47 cervername postfix/smtpd: NOQUEUE: reject: RCPT from unknown[xxx.xxx.xxx.xxx]: 554 5.7.1 <receipient_name@domain>: Relay access denied; from=<sending_address@domain> to=<receipient_name@domain> proto=ESMTP helo=<[xxx.xxx.xxx.xxx]>