Everyone who had a verified email attached to their game account and who used the same email address on forum will have their forum and server accounts merged. If that is not the case, you may still log in to your forum account using your forum account credentials, but make sure to tick this checkbox:
If you wish to connect your game account to your old forum account, but didn't meet the criteria then open a support topic and we will help you out.
New forum account registrations are closed, if you wish to use the forum, you must own a game account with a verified email address.