Every other time it goes to about:accounts?action=reauth&entrypoint=preferences and then to about:preferences#sync, this cycle keeps going on and on, email is received, but the sync does not start.

zimon, I wish you had received an answer to OUR problem. Maybe it takes two voices to get some attention. I hope so. Thanks.

I have this problem but on the android version.

I select sync, it takes me to the login page, I input the correct email and password, then it shows me that login was successful, but when I go back to the settings page it shows as if I never logged in. When I select the sync option it just takes me back to the login page. Every time I log in I receive a mail about a new login, but on the android app it still appears as if it never did. When checking the connected devices on the PC version of Firefox, it doesn't show my phone. I keep retrying every time there is an update on the Firefox app but so far it hasn't worked.

Firefox Android version 57.0.4 Android version 7.1.1

The beta version works so I've been using that for the time being.