If you are using a VM that has Adobe 2019 installed you may not be able to load HEVC/H265 content into Potplayer. Below are the steps to change Potplayer's settings to read this file format.
1. Open Potplayer from the desktop shortcut, applications menu or searching for it.
2. Once Potplayer is open select the dropdown at the top left to select the "Preferences" menu or press F5.
3. Select "Filter Control" (1), Video Decoder (2), and then the "..." next to "H.265"
4. Select the dropdown next to "H.265/HEVC" and change to "FFmpeg64.dll"
5. Click Ok and Apply to exit the menus. Your H265 can now be loaded into PotPlayer.