Uhmm... sorry to hear that. Would be possible to share the video file to test it here?  Thanks

Thanks for the quick answer! How can I share a video file? I only find a way to share pictures and there I can´t even upload one. The error message I get is "undefined".

Just share it with  https://wetransfer.com or onedrive/dropbox.... This website doesn't support video files 

Okay. Here´s the OneDrive Link: https://1drv.ms/v/s!AsOcqn6Xx6vNzBcIZrcjgr5AMxiL?e=w1d1I0

Uhmm.. weird. It plays perfectly here on a laptop with integrated graphics... :S We rely on ffmpeg for all the playback stuff... so no idea what could be happening there. Can you try upgrading your videocard graphics drivers? 

Mhm... they should be uptodate. But it doesn´t work either on the standard video player, so maybe it´s a bug of Microsoft/Snapdragon?