Don’t have a better title yet. Sometimes bug email lists are the best way to find answers!
After installing Nextcloud using yunohost (which is awesome so far), the Redis server crashed and couldn’t be restarted. Turns out a couple cifs (Samba) drives I was mounting in fstab were preventing Redis from starting.
I unmounted the drives, started Redis through yunohost, and then remounted the drives. If I have to reboot, will probably have to go through this again, so not an ideal solution.
Jul 19 22:14:46 systemd: Failed to start Advanced key-value store.
Solution figured out from: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=834551#27.