Jason, I don't know if I can help with this specific problem, but I'm also a TW customer, and I've noticed a few issues with them. 1. Multiple copies of some mail (I use their POP/SMTP servers, not Exchange), as though my connection had dropped prior to receipt/delete of mail from their servers. 2. DNS timeouts. I reported this one to them, but it is still happening. Try for yourself - use NSLOOKUP to one of their DNS servers, to some obscure site unlikely to be in cache. Frequently, I see it timeout on the first attempt, then the next attempt it is fine. Possibly? related to your problem.... They told me the same thing on the DNS timeouts, problem on my end. Funny that my own (external) DNS server works fine... - Bob Coffman -----Original Message----- From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Davis Sent: Wednesday, October 11, 2006 10:28 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Error 550 Relaying Mail Hello all, I'm scratching my head at this one.. I've helped a client - Paragoncommunities.com - change over to a new ISP (Time Warner). Since Time Warner is hosting their mail and their domain is now pointing to Time Warner's DNS servers (along with MX record change), they are now able to send and receive mail. However, when sending from my exchange server, I get intermittent relay errors when sending to their domain. Here is a transcript: The original message was received at Wed, 11 Oct 2006 10:11:52 -0400 (EDT) from mail2.csical.com [65.214.152.235] ----- The following addresses had permanent fatal errors ----- <jason@xxxxxxxxxxxxxxxxxxxxxx> (reason: 550 relaying mail to paragoncommunities.com is not allowed) ----- Transcript of session follows ----- ... while talking to fep.biz.rr.com.: >>> DATA <<< 550 relaying mail to paragoncommunities.com is not allowed 550 5.1.1 <jason@xxxxxxxxxxxxxxxxxxxxxx>... User unknown <<< 503 No recipients specified Reporting-MTA: dns; rrcs-asg-08.hrndva.rr.com Received-From-MTA: DNS; mail2.csical.com Arrival-Date: Wed, 11 Oct 2006 10:11:52 -0400 (EDT) Final-Recipient: RFC822; jason@xxxxxxxxxxxxxxxxxxxxxx Action: failed Status: 5.1.1 Remote-MTA: DNS; fep.biz.rr.com Diagnostic-Code: SMTP; 550 relaying mail to paragoncommunities.com is not allowed Last-Attempt-Date: Wed, 11 Oct 2006 10:11:53 -0400 (EDT) I've called Time Warner and they said it's a problem on my end. I'm not sure I agree because I'm not getting any relaying mail errors to any other domain in which I send mail. Any ideas? Thanks for your input, in advance. --Jason Davis