The intermediate certificate used to sign Firefox extensions expired. Active extensions are automatically disabled when Firefox checks extension certificates (daily). It is currently not possible to install new extensions.
Bug report:
https://bugzilla.mozilla.org/show_bug.cgi?id=1548973Official announcements on Discourse:
https://discourse.mozilla.org/t/certificate-issue-causing-add-ons-to-be-disabled-or-fail-to-install/39047Update - 10.20 UTC: "Update: We have rolled out a partial fix for this issue. We generated a new intermediate certificate with the same name/key but an updated validity window and pushed it out to users via Normandy (this should be most users). Users who have Normandy on should see their add-ons start working over the next few hours. We are continuing to work on packaging up the new certificate for users who have Normandy disabled." - Eric Rescorla (
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