problems importing videos into Harmony 20

I recently installed harmony 20 (I had 17 before), and when I want to import a video in mov format or the compatible ones, it does not allow me if it is for a few seconds, but it leaves me if it is 1 minute or more. The file is not damaged or with another problem, because I tried a mov that exported the same harmony with the duration of 2 seconds and it didn’t let me import it.

Why is this happening?