A colleague of mine has all her emails go to spam when emailing a hotmail address. I've tested it with several friends accounts and it always goes straight to spam, unless they say it's safe and I resend it. I've tested sending from her computer, and from a computer in another office, and via webmail.

The thing is it's strange that it only affects her. I would assume if MS had decided my company was sending out spam we all would have problems emailing people at hotmail/outlook, but it's just her. 

Is there any reason why all her emails, and only her emails, go to spam, and anything I can do to undo that?

Many thanks,

Phil