This sounds to be referring to your Mozilla Account. Mozilla is deleting Mozilla Accounts that have not been active for two or more years. https://support.mozilla.org/en-US/kb/mozilla-account-deletion-inactivity https://support.mozilla.org/en-US/kb/sumo-profile-inactive-deleted What Mozilla Accounts are used for as it is not required in order to use the Firefox web browsers. https://support.mozilla.org/en-US/kb/access-mozilla-services-firefox-account#w_what-services-can-i-use-with-a-mozilla-account