Ncp-dist-upgrade error: php7.3-fpm: unrecognized service

NextcloudPi version: 1.52.4
Nextcloud version
Debian Buster (before upgrade) with Armbian Linux on an Odroid HC-2 (XU4)

I’m trying to upgrade Debian from Buster to Bullseye so I can then upgrade NextcloudPi, and I just ran into an error:

php7.3-fpm: unrecognized service
Something went wrong. Fix it and try again

After rebooting, I checked the NextcloudPi “System Info” page. All looks OK (including the OS now showing as Armbian 23.8.1 bullseye), except “HPB service” is down.

I’d appreciate any help with this. Rather a Linux noob, but I can certainly run any commands recommended. Thanks!

EDIT: As suggested in another post regarding HPB service down, I ran “clear-php-opcache.” No change, HPB service still down.

EDIT 2: It looks like I solved it - somehow it was still stuck in maintenance mode, even after rebooting. After manually disabling maintenance mode and rebooting again, all services running, and it’s now reachable from the web.