As best as I can guess, the remote server is complaining that the format of your message does not conform to the format it expects, which would be a user at a local host in the recipient's domain. The other half of the message is that it's not a gateway, so it will not pass on what appears to be a non-local address. If you could give us the address to which you are sending, even in the format <munged>@theaddress.tld, we might be able to guess a little better. Oh, and did you munge the 550 message at all, or is that how it appeared verbatim?
FWIW, there has been some discussion of your provider, optonline.com, on news.admin.net-abuse.email in recent days, with the general concensus (hah!) being that optonline is not a spammer, just a cable modem provider with a lot of potentially abusable clients. So there is a small but existing possiblity that you are being blocked due to your address. -- be - MOS Yow! I just went below the poverty line! > -----Original Message----- > From: Jeffrey Dubyn [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, February 12, 2003 8:42 AM > To: Exchange Discussions > Subject: Strange 550 error > > > I have an issue with an Exchange 2000 SP3 server where an > email sent from > inside the Exchange organization is not getting to some > recipients in a > specific domain. I have logging turned up, and found a > strange message: > > 550+not+local+host+recipientdomain.com,+not+a+gateway > > The 550 error maps to a generic protocol error (SMTP error), > but I can't > make heads or tails out of the rest of the message. > > What is strange is that the domain comes up successfully in > nslookup and > from the Exchange server, I can connect via telnet to port > 25. The users > have had no trouble sending email to this recipient at this > domain before or > since, except for this most important email (or course). > There was no NDR, > no nothin' - just seems like the email went into a black hole. > > Thanks for any assistance! > > > _________________________________________________________________ > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > Archives: http://www.swynk.com/sitesearch/search.asp > To unsubscribe: mailto:[EMAIL PROTECTED] > Exchange List admin: [EMAIL PROTECTED] > _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED]