Disclaimer: I don’t do FreePBX, I just do stuff and things and provide assistance.
The plugin that was used on the website to provide registration broke and attempts to find a solution failed. It won’t get fixed, because Crowd and Atlassian is going away just like happened for Asterisk. This forum will be switched to standalone user management which means registration will happen directly on here, and existing user accounts will require password reset (as mentioned on the linked blog on FreePBX Jira and Bitbucket are being shut down). I don’t know when that will happen. I’ll be pushing for it to happen sooner, since as @david55 mentioned people are using the Asterisk forum for FreePBX questions and we’re really not the best place for that.