Firefox Sync (desktop and mobile) is currently having intermittent problems due to server overload.
Mozilla Services Operations is aware of the problem and is actively working on it.
If you are using Firefox and have an active Sync account, you may see an error bar appear at the bottom of the browser window:
Sync encountered an error while syncing: Unknown error. Sync will automatically retry with this action.
There may also be a “Server Status” button.
(or a similar message in English or localized)
If you track your sync log, you may see the following:
- Sync.Collection DEBUG mesg: POST fail 503 https://…
- Sync.Collection DEBUG POST fail 503 https://…
- Sync.Engine.History DEBUG Uploading records failed: “255”
- Sync.Service DEBUG history failed: “255”
- No traceback available
- Sync.Service INFO Aborting sync
- (or similar contents)
There is nothing you need to do at this point. Sync is working intermittently even though you may see the errors.
There is no need to deactivate your devices or make any changes to your account.
Once the issue is resolved, the errors should go away and Sync should function as expected.
There is also a tracking bug in Bugzilla:
Bug 690470 – [meta] Tracking bug: Sync storage nodes responding with 503
If you need to file your own bug in the future, you can use the following guide and template:
Thanks for your understanding and your patience.