That will depend on which ad-blocker you are using.

I use μBlock origin and don't have to switch it off for YouTube; if did I doubt I'd watch it much.

The best general advise I can give you is to click the jigsaw puzzle piece icon and then 'Manage extensions' which will list all the extensions you've got. Find your ad-blocker and slide the switch at the right-hand end of the line it's on to the left, ie 'off.'

There may well be a quicker way but without knowing what you're using I can't say what it is.

I appreciate the response & the input.

However... when I go to my Extensions, I don't see any 'Ad Blocker' extension. None at all.

I do have Malwarebytes Browser Guard, which I've just turned off, and I'll see if that addresses the problem. Before that, I had turned off my HP Wolf Security extension (HP being Hewlet Packard), but that had no impact.

Part of the problem is, when I select the particular video I'm trying to watch, a screen flashes by in less than half a second, literally, and as it's flashing by, I catch the merest glimpse of the words "Ad Blocker" and then it goes to a full-black screen. The screen flashes by so quickly, I can't even click on that screen with "Ad Blocker" in an attempt to stop it before it's gone ! So, I only believe I know what it's telling me.

Also, before dispatching this response to you, I tried a separate video on YouTube, and that played with no problem. Well, at least, once I clicked on "skip" for the ad which preceded the video.

I may try to reach out to Microsoft Support tomorrow (Monday), but I expect to hear "We don't know anything about problems with Firefox browsers, or YouTube."

Thanks again for your help. If you have any additional suggestions, please let me know.

Cheers.

Lee

AN ADDITIONAL FOLLOW-UP TO YOUR ORIGINAL RESPONSE:

FYI -- Apparently, disabling the "Malwarebytes Browser Guard" did the trick. I'm now watching the highlight replay from a college football game yesterday and, as best as I can judge, that same video I'm watching was the video I had been unable to access.

The "Malwarebytes Browser Guard" was included in my 'Extensions' folder, but there was nothing attached to it which indicated 'Ad Blocker'. Just for the hell of it, I'm going to re-enable Malwarebytes Browser Guard, and try the same video again.

Thanks again for the help.

Lee

It seems then that YouTube, or something, believes you have an ad-blocker when you don't.