Buffering on LG app in the Evening

Hello all,

I recently bought a LG TV (55UJ634V) and installed the Plex app and I encountered a problem that I can’t explain.
Setup:

  • LG TV (all updates installed) connected by cable directly to the router (Wifi disabled)
  • Internet speed 65 down 20 up (mpbs)
  • Plex Server is located at a different place with 1gbps upload speed

Everything plays fine on the TV, even 4k movies with 30-40mpbs bitrate until about 8-9pm every night, then I get constant buffering even at 2mpbs bitrates (direct play or transcode doesn’t matter). You might think that my ISP is bad (I thought the same) but if I play the same movie on my laptop I works absolutely flawless (also direct play, 40mbps 4k stream works perfectly when at the same time when 2mpbs movies are buffering on the TV).

What I have tried:

  • playing different files (x264, x265, 720p, 1080p, 4K, mp4, mkv) always the same symptom
  • rebooting the router
  • confirm sufficient download speeds from my server to my laptop (65mpbs)
  • confirm that it is direct playing on the TV (it is)
  • entering my server ip address manually in the LG Plex app (makes no difference)

any ideas please? I couln’t find a similar behaviour anywhere on the internet