+2
Unable to login from Firefox but with no problem in Opera. Not syncing with Firefox since a couple of days
When trying to log in it briefly shows the warning: "An error occurred, please go back to the login form"
Служба підтримки клієнтів працює на UserEcho
Check the latest update. reinstall addon and try again
https://addons.mozilla.org/en-US/firefox/addon/fvd-synchronizer/
Let us know if it works or not.