If your account has stopped working it's probably because you registered using a non-corporate e-mail address.
There is no automated way for us to keep up with all the possible free and anonymous mail services and so we have to manually check accounts from time to time and then block those accounts that have been opened using such services.
We make it very clear: if you want access to any of our Group sites, you need to register using a corporate e-mail address which will be verified before your account is approved.
If you don't, either your account will be rejected or, if it is at first accepted because the free / anonymous service is not in our list, it will be blocked when we review accounts.
If you did use a corporate e-mail address, then the most likely reason your account isn't working is because you have forgotten or mistyped your password. Click on "request a new password" at the log-in screen and make sure you remember or get it right next time!