Since the late 70s and well into the 80s currently version 88 of Firefox I had a problem with most videos displaying the following message:
"This video This video cannot be played because of a technical error.(Error Code: 200001)"

I have no proxy set and all drivers are current.
Researching I found many having same or similar problems but nobody having a solution.
That was until I came across a locked and archived forum thread: https://www.reddit.com/r/techsupport/comments/aday21/video_error/

The last reply, by "SlickStretch" was the correct answer and solution.

"solved by disabling the extension: 'Disable HTML5 Autoplay.' Try disabling/removing this extension or any similar ones."

sometimes work, sometimes not. still happy

Was working fine, but makes some videos unreadable (corrupt file, but ok when this plugin is disabled) really annoying.

This used to work fine, but in the last few days it has started BLOCKING videos in Facebook and newspaper sites. Have to disable it in these sites if I want to see videos, but then they autoplay, which is precisely why I NEED the extension! The extension is now almost useless.

Works fine for me.

Doesn't work any longer on Youtube.

Prevents Twitter videos from looping when they reach the end, which is what I wanted it to do. Also prevents IMDb videos from playing at all. And I suspect this extension might be somewhat CPU-heavy when simultaneously acting on multiple tabs, too.

Don't work on morgenpost.de
funktioniert nicht auf morgenpost.de

Works on some sites, but I can't get it to save the list of sites I want it disabled on. Removing this. Please update this add-on!

Excellent add-on. Firefox's autoplay settings don't seem to have any effect on many websites; this one does the trick. Thank you for making it.

It did not disable autoplay on Tubi. Nothing else has stopped autoplay on Tubi without breaking manual playback.

Does not disable autoplay, nor preloading.

Doesn't seem to work in my case

This is a blessing! As a person with ADD this really helps me stay focused. This works for websites where Firefox by default doesn't offer disabling autoplay.

Addon not bad, but would like to exclude some domains. Unfortunately it does not work. Must switch it off manually, if needed. It sucks.

Works fine, BUT, can't figure out how to set Per-Domain Preferences. Want it enabled for YT but disabled for everything else.

You had ONE JOB...

Doesn't work on tumblr and causes huge ram leaks on know your meme.

It doesn't bloody work!

BREAKS VIDEO on some sites .. espesially IMDB
I dont advise anyone to install this addon unless it gets a major update

Diese App blockiert unter Firefox in GMAIL beim Schreiben von Mails das Drop-down-Menü der vorhandenen Kontakte/Gruppen. Man kann Kontakte nur mehr einzeln, händisch eintippen. Aus diesen Gründen ist das Add-on unbrauchbar.