Playback Error - Unable to tune channel with Tvheadend

Hi all!
I have set-up Tvheadend with an IPTV provider, and that works flawlessly from Chrome on Windows, and the TvhClient app on IOS. I tried two methods to tie Tvheadend together with plex, first with jkaberg/tvhProxy, then with TheJF/antennas. Both resulted the exact same results, where I could get the DVR working, but I get the before mentioned Playback Error - Unable to tune channel error with most of the channels. Interestingly a few of the channels do load and work. Anyone has an experience with this method?

I run a proxy now for quite some time successfull.

Thing unwound check:

How many concurrent streams does you provider allow/make sense?
Create separate users for the proxy and other clients and work with priorities, so tvh can malte that the most important ones get served.

Just 2 things to start with …

Also compare tvh logs while starting recordings from PlexDVR to see if there is an error on tvh side as well will help for sure.