It could be 2 things one being DNS which means it cant find the ip of the pages and relay. Try setting the mail to 188.8.131.52 and see if that lets you send mail. If it does then you have a dns problem.
The other thing is that ist timing out does it allways happen or do you sometimes get to hotmail etc? It could be a problem with spyware changing the host file or causing problems. It allways worth checking for virus/spyware