I don't think forum volunteers yet know the cause or remedy for this problem. However, know that dozens of people are reporting the same thing in recent hours, so it may be due to a rolling update gone wrong.

It was working earlier, after Firefox for Windows gave out, so I was hoping it wouldn't be affected. But now even Firefox for Android has disabled my ad blocker. I can no longer visit my forum on my tablet. :(

We apologize for any inconvenience caused. A fix is on the way. https://discourse.mozilla.org/t/certificate-issue-causing-add-ons-to-be-disabled-or-fail-to-install/39047

I have this same problem. Not good. Everyone seems to have it! :(

I'm using FF since Win XP times. But I will delete it if adblock will no longer work!

Mozilla has rolled-out a fix for this. The fix will be automatically applied in the background within the next few hours, you don’t need to take active steps.

In order to be able to provide this fix on short notice, they are using the Studies system. You can check if you have studies enabled

1. Go to [=] > Options > Privacy & Security.
2. Make sure Allow Firefox to install and run studies is check marked.

I you had it disabled, you can disable studies again after your add-ons have been re-enabled.

They are working on a general fix that doesn't need to rely on this and will keep you updated.

Chris Ilias said

Mozilla has rolled-out a fix for this. The fix will be automatically applied in the background within the next few hours, you don’t need to take active steps. In order to be able to provide this fix on short notice, they are using the Studies system. You can check if you have studies enabled

1. Go to [=] > Options > Privacy & Security.
2. Make sure Allow Firefox to install and run studies is check marked.

I you had it disabled, you can disable studies again after your add-ons have been re-enabled. They are working on a general fix that doesn't need to rely on this and will keep you updated.

Don't think millions of FF users read this tread. Hope this will be not the official and only one fix of this issue.

Hi d.y.korolkov, studies are enabled by default in new installations of Firefox, so it depends on whether users turned them off. They are going to need more help, but most likely they will find the information in articles that pop up on their favorite web search engines.

Ref. About Studies

From what I've looked at so far the Android Firefox fix will take a while longer to show up (am not on my laptop so can't see if the desktop fix has been applied yet).

I'm just going to stick to other browsers until this gets settled, I guess. :/ (Incidentally, I can't believe how hard it is to find a different mobile adblocking browser that actually works well. The one I finally settled on "may not be optimized for my device.")

Hi tehuti88, there is a workaround for Android. See: https://support.mozilla.org/questions/1258163#answer-1218604

I'm leery of attempting "workarounds" since even Mozilla suggests not trying those, as they could conflict with their fixes. I'm also not very computer savvy so I don't trust myself to do it properly (or to remember to undo it once the fix is applied).

Anyway, I'm finally back on laptop, no fix to my Firefox yet, though I figure it has to be open for a while in order to...download or update in the background or whatever? I checked out the "studies" page and the fix isn't there. Thought maybe I could somehow goose it to update in "About Firefox" but it says Firefox is up to date. I'll let that window sit idle in the hopes something good will happen while I'm browsing around in (competing browser). :/

EDIT: Oh nugget, while I was typing this something happened, I think maybe it applied the fix. I'm seeing three different things.