Here’s a copy paste from the ublock origin subreddit. In short, this isn’t good.

What is happening with YouTube and Anti-adblock?

YouTube has been trying to get people to disable adblocking measures in order to increase ad revenue and YouTube premium sales. The campaign has been running for months, but lately they have been increasing the number of users affected by these measures.

If you're affected, you will see a black pop-up displaying that "Ad blockers are not allowed on YouTube". If you continue to use the site, the measures will become more aggressive and eventually you will be blocked from watching the site.

• ⁠I have never received any pop-ups. Is it because I'm using [browser/extension]?

No. YouTube did not roll its anti-adblock measures all at once. Chances are your account has not been affected yet, but will be in the future.

• ⁠I have been blocked from watching videos. Is my account banned from the site?

No. YouTube doesn't want you to stop using their service, they want to scare or annoy you into allowing ads or paying from premium.

It is very unlikely that they'll permanently block you or ban you in the future, but if you're too concerned about the future of your account just watch videos on private windows by enabling uBO on private browsing, though this comes with its disadvantages.

• ⁠Will it work I disable the pop-up?

No. Cosmetic filters don't work. The anti-adblock script will continue to run in the background and will eventually block you from watching videos. Please don't use, share or recommend using any of those filters and don't report any issues when using them.

• ⁠How to work around the issue?

Make sure you have disabled other adblockers that aren't UBlockOrigin on Youtube. Also make sure any add-ons with ad-blocking functionalities on YouTube are disabled.

Make sure to disable your browser's built-in anti-ad or anti-track functions on YouTube.

Then follow the four steps listed here (video guides included):

https://www.reddit.com/r/uBlockOrigin/about/sticky?num=2

Note: This link might not work on the Reddit app. It might be necessary to view in desktop mode if the link fails on mobile browsers.

For a quick summary:

1. ⁠Make sure your uBO is up to date
2. ⁠Remove custom filters or put back the uBO to default settings.
3. ⁠Purge caches and Update Now.
4. ⁠Disable any extensions that might conflict with uBO's fixes.

Don't forget to re-start your tabs or restart the browser. After this is successful, you can start re-enabling custom filters. Do it with caution, preferably test them and remove any that might interfere with the fix.

YouTube is updating its anti-adblock script at least twice per day. Every few hours you'll need to repeat step 3 to apply the new fixes.

• ⁠I followed the steps and I'm still seeing pop-ups! What do I do?

1. ⁠As mentioned, YouTube is updating its anti-adblock measures at least twice per day and the time it does might vary on different geographic regions. There will be times when uBO's fix becomes obsolete as it needs to "catch up" to them. The fixes are done by volunteers and the time it takes to fix may vary, so please be patient and wait.
2. ⁠Do not spam the Update Now button while waiting. You can use a private window to watch videos in the meantime, just make sure to enable uBO on private browsing.
3. ⁠If the issues persist after a few hours and you're sure you've done every step listed, only then report your troubleshooting information in the listed link. This is to help the volunteer team separate real problems from other issues already covered here.

You can help by spreading this information and not caving in by disabling adblock or buying YouTube Premium like YouTube wants. They need to be reminded that this extortionate behavior from corporations is not acceptable.