

Maybe things have improved but some years ago I was using Synology servers at work. VMs, HA, etc. They are nice at the beginning but after some time, unfortunately, the truth is that it’s just another locked down box where whether you can tweak a thing depends if it was made possible by Synology. And while I’m not some kind of NextCloud master, I can see how it could require some tinkering from time to time. For sure it’s better to “just do it” and migrate if it’s not enough instead of not getting into the thing at all. But if I were on your spot I’d either go with something less humongous on Synology or NextCloud on docker
Use the hostname that is reachable on docker instead of IP. I think in this case that would be
plex(name of docker service/container(?))Go to access logs in pangolin dashboard and try to find out at which level the problem occurs. Where’s the last spot you see your query? Pangolin? Newt? It disappears after newt? Your plex service logs something about the query?