Some videos won't play in background
Some popular video websites have changed their settings on the server side so that videos will no longer play in the background.
I can't play videos or audio on Firefox for Android 5.0 (Lollipop)
If you're using Firefox on your Nexus 9, you might have experienced a temporary issue with playing video and audio files. We'll show you how to resolve them.
How to send a crash report on Firefox for Android
How to send a detailed crash report.