Been facing a tricky problem for the past 4 days. Some genuine paypal emails are not arriving and i began to investigate the source of the problem. I checked all the spam folder and none found. I began suspicious that it had got to do with the paypal but still i wanted to investigate my server. I checked the logs /var/log/exim_mainlog and no
> cat /var/log/exim_mainlog | grep mail@example.com
and then the root cause of the problem shows up. It seems like my mail server is rejecting all emails and because of incomplete sender verification (hostlookup failed). Sender verification is usually enabled to prevent spam the server checks backward if the host and ip are real mail server. If that fails email is rejected or temporarily put in queue.
2013-03-27 23:42:18 H=xxx F=<member@paypal.co.in> temporarily rejected RCPT <sales@prurgent.com>: Could not complete sender verify
2013-03-28 00:28:57 H=xxx sender verify defer for <member@paypal.co.in>: host lookup did not complete
The easiest way to fix is go to exim settings and disable the sender verification. Another issue could if there are incorrect ips in the /etc/resolv.conf and dns could not be resolved. Double check this file too!
