Repost from related thread (different OP?):

Despite what your ISP says, the message is coming from their server, not OE.

Did you "visit http://coxagainstspam.cox.net for more information" before
you called your ISP??

If you send such a message to 10 or 25 recipients, do you get the same error
message?
--
~Robear Dyer (PA Bear)
MS MVP-IE, Mail, Security, Windows Client - since 2002
AumHa VSOP & Admin http://aumha.net
DTS-L http://dts-l.net/

WOLLAM wrote:
In Outlook Express 6.0 wife attempted to send a Group email and which was
returned as undeliverable due to the following error message:

The message could not be sent because its size exceeded the server's
limit.
You can use the option, located in Tools | Accounts | Properties |
Advanced,
to break messages into smaller parts. Subject 'Hello', Account:
'pop.west.cox.net', Server: 'smtp.west.cox.net', Protocol: SMTP, Server
Response: '552 5.2.0 NmhK1b00L3hcpaG04mhKj9 This message was
undeliverable.
This message has been found to be a potential spam message, and has
therefore been blocked. Please visit http://coxagainstspam.cox.net for
more
information.', Port: 25, Secure(SSL): No, Server Error: 552, Error Number:
0x800CCC6D

This was attempted to a Group of 83 recipients, and the message size is
5kb.
So far, the best Cox could tell me is to check that the 'syntax' of all
recipients in the Group is correct; they are.
Thanks in advance for any and all help.