I had big issue with our customer Lync online login. Old IT support had move emails local exchange to Office365. But i they wont uninstall exchange 2007 only shutdown it.
domain user cannot now login to Lync online if computer is domain member.
but if i made new user account to domain that can login to lync online correctly with same computer. New user doesnt have AD attributes to exchange. If i login to computer with domain administrator also i can login to lync. Domain administrator has exchagen attributes. Problem is only with user what are in some OU. i take gpresults txt to attach