COMPOSE NOT WORKING

I have a Win XP Home computer in which I run Seamonkey which is
a form of Netscape. I use both Yahoo web mail and Mail & Newsgroups
in Seamonkey. My Yahoo works fine but in seamonkey I can receive
but not send e-mail. I keep getting the message the server has refused
the mesage. I have not changed the settings for the accounts but
put a laptop beside my computer and verified the settings are exactly
the same yet my laptop works fine. It has Win XP Home also. Then I
discovered the same thing was happening in Thunderbird which is
firefox. The setting are exactly the same but the laptop will send
and the computer will not. The receiving of e-mail works fine for all.
How do I fix this. I deleted one account in seamonkey reinstalled it
but same thing happens.

Jerry

Posting an exact, complete copy of the error message you are getting might be helpful.

Compose does work on one of my computers, but not on another one
with the exact same settings. This appears to me to be a YAHOO
problem. They have changed something. The error message read 553,
e-mail address not verified. All my e-mail addresses are verified.
I checked with Yahoo support. All they will tell me is they do not
support Seamonkey-Netscape.

Jerry

If there is a "My server requires authentication"-type setting in Seamonkey, try it.

Also, if there is a "Log on to incoming mail server before sending mail", try it as well.

If neither of those work, or are not available, see if you can setup to Send email through your ISP's email server instead of Yahoo.