I have been having trouble for about 2 weeks now when I try to send an email to multiple addresses using Thunderbird. If I send a message to 1 person, no problem. But when I send a message to more than one person I get an error message like this "An error occured while sending mail. The server responded 'not our customer'. Please verify that your email address is correct in your Mail preferences and try again." What is going on? I've checked and verified all my settings are correct. Now what???
"Not our customer" occurs when you send to an @comcast.net address, but there is no such account. Are you sending to other Comcast customers? If not, are you sure you put the appropriate @domain suffix on each address? Maybe the problem is with how you're separating the addresses in the list.
ok, duh! I had no clue that is what it meant! Thank you so much for clearing that up for me, I was so frustrated! I found out who the troublemaker is too, lol...my son...changed his email addy and forgot to tell me...it works now! Thanks a million!
My wife is having the same problem. My mailer at work sends messages to the valid addresses, and reports the invalid ones. It would be great if Comcast did the same thing. We have a distribution list that has about 80 names, and when it fails, I have to test 20 at a time to find the culprit.
Comcast DOES report which ones are invalid. The way a mail client interacts with the server is that it sends the addresses one at a time, and the server sends back a success or error code for that address. So the client can easily tell which addresses resulted in errors. Unfortunately, for some reason most mail clients don't pass this information on to the user, they just say that an error occurred.
See this thread for instructions on enabling logging in Thunderbird to find the bad address.