no compatible source was found for this media

I get this message,

no compatible source was found for this media

when i try to watch anything on crunchyroll.

I cannot get any videos on reddit or Netflix either but YouTube is working fine. I am using Firefox 64.0 and the sources work in chromium.

Videos were working earlier.

Edit: Solved it by installing GStreamer Multimedia Codecs

2 Answers

Option 1:
Try sudo apt install libavcodec-extra
According to this answer:Firefox html5 video support
Restart Firefox when you are done.
Option 2:
Installing GStreamer Multimedia Codecs

The media codecs for ubuntu are not installed by default. Install the media codecs by

sudo apt-get install ubuntu-restricted-extras