The internet went out, but I had some tv shows I wanted to watch already downloaded and indexed by my Plex server. So I tried loading Plex locally from my phone and it kept trying to "phone home" to have me login to the Plex website, which failed due to not having any internet access.
(I say "feature" but of course what actually happened is that the plex developers decided to block requests from outside the LAN unless you sign up for their SaaS offering, which is kind of the opposite)
Getting plex pass is a must if you use it regularly in order to support hardware encoding.
Had to enable hot spot on my phone briefly when I had an internet outage. Annoying but now just works.
My main complaint with Plex is local searching is hit and miss - a little while back I typed in a string I knew was in the title of a file (confirmed using 'locate' in CLI) and it returned 'no results'
I used extf4 as storage, but changing to NTFS (yuck) has caused less issues. With the last version the search for subtitles is broken, but at least I can add them manually. I bought Plex Pass for life, but stayed with the free version because it's more stable.
I'm on the monthly plan because I wanted to play with GPU transcoding - despite what a lot of folks say it does work in Windows on an AMD iGPU, although I've switched to discrete now (previous server was Ubuntu, but Linux GPU fan control seems to be a mess and we all know the Nvidia driver saga)