If your home internet speeds are 25mbps or less I’d recommend going into your quality settings on any home devices and setting it to adjust automatically. This will adjust the quality of the content you’re streaming based on your internet speed.
on Plex Web go to the settings icon in the top right, then go to Quality on the left and check Automatically adjust quality
on most Plex TV apps go to the menu on the left and scroll down and select Settings, then scroll down to Video Quality and turn Automatically adjust quality on
other Plex TV apps may next the Automatically adjust quality setting under the Internet Quality drop-down; in which case simply select it from the given options.
on iPhone and iPad select the hamburger menu ☰ in the top left next to Home. Select the gear icon, select Quality and enable Automatically adjust quality.
Changing this setting will prevent endless buffering in the event you go to play something that’s available on Nevflix in 4K but your internet isn’t fast enough to stream it. Instead, the server will take that 4K file on my server and transcode it to whatever the highest quality your internet speed can handle; then delivering it to your TV quicker.
If you have issues enabling the “adjust automatically” setting on your device, please reach out to me directly.