Plex ended support for some older TVs. Announcement: Plex support is ending 2020-09-30 on older smart TV devices
Here’s a possible workaround. The thread references a Samsung, but it might work for LG as well.
Error pin activate
If that does not help, then, as @SE56 mentions, consider an external streaming device such as a FireStick 4K, AppleTV 4K, Roku, Nvidia Shield Pro, etc.
Also a +1 for LG OLEDs. I picked up a B7 during the “Black Friday” sales three years ago. It has an incredible picture and has given me zero problems.
The 2012 Samsung it replaced is still in service at a family member’s house, with an AppleTV for streaming services. It still has a very good picture for an eight year old 1080p set. The ATV interface is much better & faster than the Samsung when using Plex/Netflix/etc (not a surprise given the age of the CPU in the TV vs the CPU in the ATV).
