I have Lotus Domino 8.5.3 FP6 mail server. When our user sends email to specific (two or three domains) the mail returns with following error:
Error transferring to mx10.MULPHICO.PK; SMTP Protocol Returned a Permanent Error 550 Empty envelope senders not allowed
I have proper SPF record published for my domain. Symantec Premium Antispam is installed domino server as well. All dns/reverse dns records are properly in place.
This doesn't happens with all domains, but some of them do return our emails. Is there any thing I can do at my server level ?