Why Can't My Mother Send E-mail's?

[Striker]

My mother cannot send anybody e-mail's. But she can recieve e-mail's. When I try to send myself an e-mail from her computer, this is the error message I get:

The message could not be sent because one of the recipients was rejected by the server(Her ISP's Server???) The rejected e-mail address was(in this case, my address). Accound: 'mail.televar.com' Server: 'mail.televar.com' Protocol: SMTP Server Response: 550 not local host yahoo.com, not a gateway Port 25 Secure(SSL): No, Server Error 550 Error Number: 0x800CCC79

This has got me totally stumped!!! Is there a setting that's wrong on my mother's computer?
Is there a setting that's wrong on my computer? I checked her blocked addresses list and my address is NOT on it. By the way, I reformatted her hard drive a few month's back and she claims that ever since i did that she hasn't been able to send e-mail's. So that may have something to do with it. Maybe? Any help would be appreciated.

[glc]

What is her e-mail address (replace her username with xxxxx's)?
How is she connected to the Internet?

Sounds like she has a private domain e-mail address but is using AT&T/Yahoo to connect.........

[Striker]

her e-mail address is xxx@televar.com
My parents are on fiber optics.
Replace her user name with X's??? What will that do? I have no idea if it's a private domain e-mail address. What else do you need to know?

[glc]

I meant do NOT post her actual address here! Replace her username with xxx's in THIS THREAD. I just edited it for you.

She needs to contact her ISP and get them to walk her through the correct settings in her e-mail client. I just tried to load up www.televar.com and it does nothing.