Hi degnmozilla, it's not a problem with the add-ons.

A critical Add-on-related certificate expired (which obviously should not happen). As a result, all verifications for that certificate are failing, preventing many extensions from being used, updated, or installed. So it's not your connection; it's everyone's connection.

The Add-ons team is working on a fix for this. Official updates are expected to be posted here:

https://discourse.mozilla.org/t/certificate-issue-causing-add-ons-to-be-disabled-or-fail-to-install/39047

Currently, the only workaround for the regular release of Firefox is to set your system clock back (for example, if your date is May 3, set to May 2; if your date is May 4, set to May 3). You might have to reinstall extensions after that, or maybe Firefox will detect the difference at your next shut down/restart. Changing the date may have other consequences, so I understand this option isn't ideal.

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.

Same problem... My Firefox was ok till around 2-3PM CST 5/4/19 when I rebooted for a Microsoft update. Upon rebooting and starting firefox, like 90% of my add-ons stopped working and ended up in the Legacy area... I just tried resetting my clock as above, closed and restarted Firefox... Add-on's still listed as incompatible.

Allow studies run is checked, and HAS been basically since installing firefox... update-xpi-signing-intermediate-bug-1548973 isn't listed in the list of studies, neither as ongoing, no complete... what I have listed is:

prefflip-push-performance-1491171 hotfix-reset-xpi-verification-timestamp-1548973 hotfix-office365-legacy-keycode-and-charcode hotfix-disable-websockets-over-h2-65-1523978

abd these have been the ONLY ones listed since 5pm CST

Hi Vanidor73, has your Firefox gotten the studies by now?

That is the only officially supported solution as of this moment; a "Firefox 66.0.4" update is expected later today. However, if your patience has run out, or you run a different version of Firefox, you could consider two other measures:

The study downloads a hotfix extension, and the hotfix extension installs a new certificate. So your options are:

(1) Download the hotfix extension directly and see whether it works (not officially supported; does not work in Firefox 52 ESR)

I know this URL looks totally strange, but this is the one I have:

https://storage.googleapis.com/moz-fx-normandy-prod-addons/extensions/hotfix-update-xpi-intermediate%40mozilla.com-1.0.2-signed.xpi

("Normandy" is the system for managing studies.)

When installing from random sites, Firefox will tell you the site does not have permission to install and present the "Allow" "Dont' Allow" drop-down panel. You would need to click "Allow" to proceed to the next step.

(2) Install the certificate directly and then manually trigger re-verification (not officially supported)

I've posted detailed steps for Firefox 52 ESR users. The screens are a bit different in Firefox 56+, but you would use the same technique. See: https://support.mozilla.org/questions/1258165#answer-1218833

jscher2000 said

Hi Vanidor73, has your Firefox gotten the studies by now? That is the only officially supported solution as of this moment; a "Firefox 66.0.4" update is expected later today. However, if your patience has run out, or you run a different version of Firefox, you could consider two other measures: The study downloads a hotfix extension, and the hotfix extension installs a new certificate. So your options are: (1) Download the hotfix extension directly and see whether it works (not officially supported; does not work in Firefox 52 ESR) I know this URL looks totally strange, but this is the one I have: https://storage.googleapis.com/moz-fx-normandy-prod-addons/extensions/hotfix-update-xpi-intermediate%40mozilla.com-1.0.2-signed.xpi ("Normandy" is the system for managing studies.) When installing from random sites, Firefox will tell you the site does not have permission to install and present the "Allow" "Dont' Allow" drop-down panel. You would need to click "Allow" to proceed to the next step. (2) Install the certificate directly and then manually trigger re-verification (not officially supported) I've posted detailed steps for Firefox 52 ESR users. The screens are a bit different in Firefox 56+, but you would use the same technique. See: https://support.mozilla.org/questions/1258165#answer-1218833

no it hasn't shown up, and I click on the link, click Allow and get: support.moxilla.org The add-on could not be downloaded because of a connection failure

So it won't even LET me get the file it needs IN ORDER TO FIX IT!

UPDATE: Firefox 66.0.4 and 60.6.2esr are now available with the new certificate needed to solve this problem. See: Update Firefox to the latest release.

Vanidor73 said

The add-on could not be downloaded because of a connection failure So it won't even LET me get the file it needs IN ORDER TO FIX IT!

You can wait for Firefox 66.0.4 or try the other workaround if you can't wait.

Checking "Allow Firefox to install and run studies" under "Options/Privacy and Security/Firefox Data Collection and Use" fixed the problem for me.