Hi,
recently I migrated from eFa 4 to eFa 5 on a brand-new CentOS 9 stream machine. All went well, but now I see a strange behaviour.
Some E-mails (mostly from t-online.de) are delivered over and over again. On my Exchange 2019 box the mails are recognized as duplicates and don't appear in users mailboxes. Nevertheless the sender will get a "delayed delivery" notification and after some time an "undeliverable" message from his mailserver.
How could I find out what is causing this issue? I tried with "Debug = yes" in MailScanner.conf with no avail.
Regards
Mark