I have been stuck to this problem on Linode Server. I was not able to send mails to my primary domain. It was giving following error in mail logs.
Nov 18 13:20:06 indidelights sendmail: sAI7o6ST004820: to==?utf-8?B?Uml0dSBB?= <email@example.com>, ctladdr=auriga (1001/1001), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30853, relay=[127.0.0.1] [127.0.0.1], dsn=5.1.1, stat=User unknown
Apache was trying to handle the email locally on our server. When I looked at the log response I saw it was returning the following error.
550 5.1.1 firstname.lastname@example.org
After following these steps the email was routed to the correct mail server. My setup is Ubuntu 12.04 with PHP 5 Apache2 and Sendmail.
- Edit the sendmail config file on the Apache server:123sudo nano /etc/mail/sendmail.mc
- At the end of the file add the following lines of code to handle email correctly:1234define(`MAIL_HUB', `example.com.')dnl define(`LOCAL_RELAY',`example.com.')dnl
- Save the file and exit.
- Update the sendmail setup in the command prompt:123sudo sendmailconfig
Follow the steps, I said yes to everything
- Restart sendmail:123sudo service sendmail restart
- Try sending the email again. It should work now.