SMTP Proxy incoming - sender receives 451 error

Eminho

Hello,

different senders get error while sending mails to my customer (firebox m390). This error the sender get:

Diagnostic-Code: smtp; 451 Requested action aborted: local error in processing

On Firewall log i get only this logs about that (debug is active):

2023-05-07 00:51:53 FWStatus, 0x3ac5e0e0-1403678 Queue empty, payload 'MAIL FROM: SIZE:84347\x0d\x0a' stays with event, pri=7, proc_id=smtp-proxy, msg_id=
2023-05-07 00:51:53 FWStatus, 0x3ac5e0e0-1403678 MAIL FROM: SENDER, pri=7, proc_id=smtp-proxy, msg_id=
2023-05-07 00:51:53 FWStatus, 0x3ac5e0e0-1403678 986046688:1403678: smtp command 'MAIL FROM: SIZE:84347\x0d\x0a', pri=6, proc_id=smtp-proxy, msg_id=
2023-05-07 07:06:53 FWStatus, 0x3a2b37e0-66144 Queue empty, payload 'MAIL FROM: SIZE:84347\x0d\x0a' stays with event, pri=7, proc_id=smtp-proxy, msg_id=
2023-05-07 07:06:53 FWStatus, 0x3a2b37e0-66144 MAIL FROM: SENDER, pri=7, proc_id=smtp-proxy, msg_id=
2023-05-07 07:06:53 FWStatus, 0x3a2b37e0-66144 975910880:66144: smtp command 'MAIL FROM: SIZE:84347\x0d\x0a', pri=6, proc_id=smtp-proxy, msg_id=

Does someone has an idea?

james.carson

The firewall isn't seeing any payload traffic -- the sending MTA might be waiting for something.
the 451 from the server suggests that the problem may be on the sending or receiving side. Office365 uses 451 as a rate limiting response, so if the problem fixes itself, it's likely that.