The ZBB is back.
The brief story: Bluehost upgraded the scripting software, php. The forum software, phpbb, doesn’t work with the new php. Bluehost did not bother to inform clients about the upgrade, and only of three reps I talked to even understood the issue. And they didn’t seem to know what phpbb was.
On the plus side: it was clear what to do, namely upgrade phpbb. This went smoothly enough, though it was tedious and took most of the afternoon. Bonus, I have a FTP client now that I know works.