Thank you, thank you Bruce and Ricky!! Checking the "Authentication" box
fixed it. I wonder why it wasn't working before since I have done nothing
with my accounts? I don't know whether the box was checked or not before the
problem. Can in arbitrarily uncheck or work without it being checked?
Again, your help was appriciated! Have a great day. Bob

"Ricky" wrote:

On the tools..accounts..mail..properties..server tab make sure the 'My
Server Requires Authentication' box is checked.

"Bob W" wrote in message
...
Thanks for response, Bruce.
I have already phoned Comcast and these were correct: POP3;
mail.comcast.net; smtp.comcast.net. Is that what is meant by
"authentication
checked"?
Bob

"Bruce Hagen" wrote:

Tools | Accounts | Mail | Properties | Servers. Is: My Server Requires
Authentication checked? The error message suggests that it should be.
--
Bruce Hagen
MS-MVP Outlook Express
Imperial Beach, CA


"Bob W" Bob wrote in message
...
Outlook Express has been used for a long time with no problems and nor
alterations have been made. 4 days ago the sent emails were rejected.
I
turned off computer over night and it worked again the next day. Then,
yesterday, the sent emails were rejected and I shut off computer
overnight.
Error problem still exists. Receiving emails works OK. I can send OK
through webmail at Comcast, but not from OE. Here is the Microsoft
error
message:

The message could not be sent because the server rejected the sender's
e-mail address. The sender's e-mail address was
'.
Subject 'testing', Account: 'Bob Wilmot', Server: 'smtp.comcast.net',
Protocol: SMTP, Server Response: '550 5.1.0 Authentication required',
Port:
25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC78