i'm having a big problem with emails ..i get the same 451 message for some emails..it took me a while till i noticed in which cases this happens..and i finally think that i'm able to conclude that emails with attachements sent to a distribution list, or event to multiple addresses are having big chances or getting stuck in the deferred queue with the message :
"status=deferred (host localhost.localdomain.com[192.168.29.5] said: 451 4.0.0 Temporary message delivery failure try again (in reply to end of DATA command)) " . This is a big problem for our mail system because we really must be able to send and receive emails with attachments .. i'm running Release 4.5.5_GA_838.SuSEES9_20070503173634 on open Suse 9.3 . i also have installed two other zimbra servers on open suse 10.2 (one is network edition and one is open source..and everything seems to work ok there...
)
i tried to increase max attachment size with mprov mcf zimbraMtaMaxMessageSize 20480000
but things didn't really changed...today i got a new message stucked in the deffered queue..fifth one in ~ 3 days..
please advise .
thanks.