If you plan to use a Powtoon as your Facebook cover video, you need to download your Powtoon to an MP4 file and select the following quality setting in the export process:

Important:
1. Powtoon size must be 820 x 312 pixels (minimum), with Facebook's official
recommendation being 820 x 462 pixels.
2. Powtoon duration must be between 20 - 90 seconds.
recommendation being 820 x 462 pixels.
2. Powtoon duration must be between 20 - 90 seconds.