My plex is Plex unstable

Hi, I’m using Plex since a year -i think-.
It’ s getting to be unstable.
The case is, I’m running Plex server on debian. I have a mini pc for server with an intel J1900 processor.
It handles the transcoding well. That’s not the problem.
I have clients on many devices. LG Webos, iOS, Android, Windows Phone, PC, Samsung Smarthub.

It often hapens, that on the same Network one device cal see my server and other can not. e.g. My doughter waches some TV shows on iPad, an ipad app goes dark and exists. If i restart it i can continue the film. Sometimes, it can not be restarted, because it does’n see the server. Meanwhile an other TV show from te same server is playind on The WebOS client constantly.
In Other times The WebOS tv doesn’t sees the server, but i can Access the server from my windows phone. If I log in to web app usein my local address (192.168…) then server is accessible, and it shows that the server is fully accessible from remote locations, and it’ logged in. If I log in to Plex.tv, then is shows that the server is offline.
And not to mention that from remote locations, is nearly impossibe to wach a whole film, because after 20-30 minutes any client disconnects. Then sometimes they can continue, sometimes they show, that the server is offline. and after some time it’s online again.

Recently my ISP had my router replaced. But the problem is still there with Plex.
Please advise which logs or setting I should send, and where to find them.

Regards,
Andras

I have a feeling no matter what logs you produce, it’s going to come down to a issue with your network setup on a hardware or OS level, not Plex. You mention yourself how you’re able to access from one device while another works. You should focus your energy on that.

i’st getting even more frustrating. I Moved. New ISP, new Router.
Only 2 machines on the Network: Plex server, and my laptop. Laptop is running Win10.
I have Win10 plex app. Plex Home Theater, Plex Media Player, And of course browser.

Win10 app looks great! but it doesn’t play anything. It opens the media but never starts playback.
Plex from browser is working
Plex Media Player is working but it cannot set to full screen on the secondary Display…
Plex Home theater doesn’t see my server… (i’m signed in)

Windows phone app shows (MF_MEDIA_ENGINE_SRC_NOT_SUPPORTED … )
Android app played the same media, but currently it has lost connection to server.

While I was writing this it seems Plex server became unavailable.

I’m going to reinstall my plex server. I will give a try to a Windows based server…
Hopfully it will work better…

Same Hardware, but windows10, and Plex server works, and has none of the issues I mentioned above.