Sorry for the generic title, I have no idea what went wrong.

https://commons.wikimedia.org/wiki/File:Maalwerk_Volmolen_Frankenhof.mp4.
(https://upload.wikimedia.org/wikipedia/commons/0/0b/Maalwerk_Volmolen_Frankenhof.mp4):

An exception occurred: TaskError: /usr/bin/ffmpeg -y -i /srv/v2c/output/c3579c4f1aa71d85/dl.mp4 -threads 0 -skip_threshold 0 -bufsize 6000k -rc_init_occupancy 4000 -qmin 19 -qmax 19 -vcodec libvpx-vp9 -tile-columns 4 -f webm -ss 0 -aq 6 -ar 48000 -acodec libopus -pass 2 -passlogfile /srv/v2c/output/c3579c4f1aa71d85/dl.mp4.vp9.webm.log /srv/v2c/output/c3579c4f1aa71d85/dl.mp4.vp9.webm Exitcode: 1

https://commons.wikimedia.org/wiki/File:Ground_Nesting_Bee.mp4
https://upload.wikimedia.org/wikipedia/commons/6/69/Ground_Nesting_Bee.mp4:

An exception occurred: TaskError: /usr/bin/ffmpeg -y -i /srv/v2c/output/cd03195311728576/dl.mp4 -threads 0 -skip_threshold 0 -bufsize 6000k -rc_init_occupancy 4000 -qmin 19 -qmax 19 -vcodec libvpx-vp9 -tile-columns 4 -f webm -ss 0 -aq 6 -ar 48000 -acodec libopus -pass 2 -passlogfile /srv/v2c/output/cd03195311728576/dl.mp4.vp9.webm.log /srv/v2c/output/cd03195311728576/dl.mp4.vp9.webm Exitcode: 1