Can't download files from my mega storage through Ipad pro file app - "couldn't communicate with helper application"

Hi, if i try to download a video file on my iPad in my "file" folder directly from the Mega tab I get this error and won't let me. I could download a couple of times before but then stopped working altogether. Exiting and logging again did nothing, and neither uninstalling and reinstalling Mega app. Of course it won't let me reproduce mkv files directly in the app or i wouldn't have bothered.

What do i do?