Why doesn't Mail recognize valid outbound domains??

[michaelsanford]

Too often to be more than a passing annoyance, i get this error message from Mail:

ERROR
This message could not be delivered and will remain in your Outbox until it can be delivered. The reason for the failure is: This message couldn’t be delivered because the SMTP host smtp1.sympatico.ca did not recognize any of the recipients.

1. I (don't think) it's my SMTP server, I've tried the 3 I have access to and I get the same error;
2. It's not the addresses, because I've sent many things to those addresses (and domains) before;
3. Sometimes it pops up, Microsoft style, more than one of the same error panels for one message;
4. After a few hours some of the emails get through, then more percolate until it finally sends all of the ones in my outbox.

By the way, one of the outgoing messages was to the same domain (sympatico.ca) as my SMTP server

This is really starting to make me , anyone else experience this seemingly random problem, or have found a solution? Could it have anything to do with the ISP DNS system (i.e., somehow the DNS servers on my 3 outgoing servers died, and don't know that the addressees' domains exist, or something?)

 

[slur]

I've only had this problem when the address in the outgoing FROM header was different than that of the SMTP server I was using. If you can see that the FROM header is correct for the server you're using then it's a mystery.

Are you using version 1.2.3 of Mail?

 

[michaelsanford]

My SMTP server doesn't care where the mail's coming from. I use @mac.com as my primary address, and it's always worked before (well 95% of the time at least).