This error means the device being used to join a Parsec stream is having issues handling the stream. There are multiple potential fixes, described below.
Issues with the N version of Windows
If you have Windows 10 N, you need to manually install the Media Feature Pack to use software decoding. See how to get the Media Feature Pack.
Lower the resolution of the host
Try lowering the resolution on the computer you're joining, then try connecting to it again.
Update your graphics drivers
Get the latest graphics drivers for the graphics card of the machine you're using to join a computer.
If everything else fails, use software decoding
If you're not on Android, you can change Parsec's settings > Client > Decoder to Software. You may also have to revert settings like H.265 to disabled, to ensure software decoding is used.
This will allow Parsec to at least work, although with worse performance. If you have really old hardware (anything older than "Recommended" in the client requirements), this will be your only choice.