hi dionix, if you are referring to a recovery key this means you were using sync 1.1 ("old sync"). mozilla has shutdown and decommissioned its old sync infrastructure and servers end of september - this was communicated in product and by announcement at https://blog.mozilla.org/services/2015/07/31/shutting-down-the-legacy-sync-service/ old sync data will be gone if you have not upgraded to new sync in time! you can also transfer data from your old device by [[How to update to the new Sync|updating to new sync]] there or by [[Recovering important data from an old profile|migrating it manually]]...