I use Outlook Express to check my school e-mail, and it works fine but I can't seem to reply to or send e-mails to Yahoo addresses, or .rr.com. It works when I access my e-mail on the website, but I'm lazy and prefer OE. I already asked my school's computer help people, but they gave me a BS answer that didn't help at all. I can receive e-mails from those addresses. It's kind of irritating since my aunt has a Yahoo e-mail and she e-mails me a lot.
So can anyone tell me why this is happening, or how to fix it? If not, any suggestions for a program similiar to OE that's free and easy to use?
-edit- Forgot to include the error I get, but punk_is_so_dead made me remember.
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'email@example.com'. Subject 'blah', Account: 'pop.nmu.edu', Server: 'mail.nmu.edu', Protocol: SMTP, Server Response: '550 5.7.1 <firstname.lastname@example.org>... Relaying denied', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79