Most ISP's will have a help page for email, which will detail exactly how to setup accounts to work with outlook. I'm no trying to teach your granny to suck eggs, but likely as not as Saab says, there is some small change there that knocks the accounts out.
I just set one up & it wouldn't poll - it was driving me mad until I noticed I'd set it up as auth.smtp1and1 instead of auth.smtp.1and1. It's always the little things
