Rejected e mails on MS Exchange 5.5 service pack 4

[Puzzledazed]

I am getting e mails rejected with the following message :-

The following recipient(s) could not be reached:

(ADDRESS DETAILS) on 15/10/02 10:39
Unable to deliver the message due to a communications failure
The MTS-ID of the original message is: c=US;a= ;p=FASHIONFABRICS;l=FFSERVER01-021015093512Z-14
MSEXCH:IMS:FASHIONFABRICS:FFSERVER01:FFSERVER01 3502 (000B09AA) 502 Command Not Implemented

I have searched the MS Knowledgebase with no luck. Confusingly, the e mails do some times go through. The ISP is adamant there is not a problem with their service, although, they recently changed their procedures to stop block sending of spam through their server.

 

[brontosaurus]

I would lean on your ISP a bit more. The 502 error doesn't crop up until at least the "SEND" phase of SMTP conversation, which means that your server went through the HELO, MAIL, RCPT, DATA phases without a hitch. Hard to imagine that your server would be screwing up the SEND...