Alerts problem

I’m using msn messenger. When I signed on today the alerts box comes up then I click on the top of the contact list alert then another box comes then hit cancel, but after that the contact list went away saying that I have to sign up to alerts. This happened first time. Then I had to sign out to msn then reconnect again. Dıd the same thing over no problem. Why did it do that I wonder? By the way I’m using msn messenger version 6.2. Hope that made sense.