strange timeout problems

I'm trying to investigate strange timeout problems with microsoft passport.
The problem is that trying to get to any website that uses passport (tried, does not work and times out and going directly to causes redirect to where browser
waits some time and then also times out (happens with both explorer and firefox).

  I would have considered it to be unique problems with particular install
except that I have confirmed that it happens on multiple computers and I do not see any pattern either in subnet or in their config. I'm also unsure when this started as none of the computers are regularly used to
access webistes that use passport.

  So if somebody ran into something like this before and knows of any
network-related issue that could cause this, please let me know
(possibly dns or specific filter could cause it?).

Could this be relate to the fact that Microsoft nixed the Passport service
back in January?