What did you do to cause this? Setting $conf['general']['authorized_only'] = true; will cause Traq to not allow users to access the registration page.
What page were you on? Login
Describe the defect: Users can not register
Not to reopen by any means, but is support for 2 just dropped?
Support hasn't been dropped, but new releases of 2.x are going to be rare. I may release a 2.2.1 to fix the issue you reported plus a few others people have mentioned. Probably in a day or so.
Irrelevant to Traq 3.0