Kmail configuration

I have Redhat 7.2 and w2k on same machine.I have Comcast Cable Internet. Innitially my Kmail(Redhat KDE mail) worked great. Set everything just as it was set in w2k.Uses SMTP(port25) and POP3(port110).All the sudden after a couple of days the POP3 server at Comcast won’t let me in. Rechecked all settings in w2k and Redhat and nothing had changed. What’s going on. It’s almost like they’re screwing with me cause I’m running Linux cause Outlook Express in w2k still works great.