I can login fine but when I try to find any coop terrorist hunt or story matches there are none. I have no problem with the verses matches though.
I reported the problem to ubisoft support, but they told me to contact Xbox Live support. This made no sense to me since I'm playing on my PC.
Oh yeah, forgot to mention that I purchased this game from a major retail store. Also, this is a recent problem. All aspects of the game functioned fine when I first installed it.
Same thing was happening to me and I found that by making my filters to search for all in all modes (Story, Terrorist Hunt ad and Versus) will allow me to find the matches .....hope it works for you too.