I'm having a similar problem with sending emails but am able to receive but am not on ntl bb am on freeserve. Everything was fine until a couple of weeks ago and then i started getting the same message as you
But in reverse..... since you can send but not receive.
I checked my site's domain for any trouble shooting advice and this page gives me a possible explanation for mine....... that Freeserve has decided to block my outgoing mail port for any isps but theirs
I haven't tried the telnet querying option that is advised to check if that is the problem but thought i'd share it with you to see if you wanted to check to see if it was the problem with yours.
http://www.aota.net/Troubleshooting/port110.php4
I will have to check port 25 or course but you can send unlike me
Not sure why your dial-up should work and not your BB, although they are different services so thought i'd offer this up as a possible explanation just incase
This may well be a completely STUPID idea but thought i'd take the risk and post even if i do look like a complete trog
