Update: Mozilla released a Firefox update fixing the issue, version 66.0.4 has the fix.    An expired certificate in the Mozilla's add-on infrastructure is disabling all Firefox extensions and is also preventing users from re-installing the add-on. Malwarebytes Browser Extension BETA has also been impacted by this outage and is continued to be impacted.  Mozilla has acknowledged the issue and updates from Mozilla's team can be tracked here: https://discourse.mozilla.org/t/certific