Hi , today i tried to sign-in to my firefox sync account, but it wont going through and its saying working , and it wont login , and its very weird because i never had this kind of problem before , and login 4 days ago to my firefox account and everything was fine but now i don't know why its not let me to login

Hi   !
Usually, when this gets stuck on   'Working',   it means some error has occured. Could you please check in the web developers console for any errors or failing network requests,   by pressing   Ctrl + Shift + k   ?

Hi the thing is i checked everything and to be honest Its All this shit started when i upgraded my firefox to v50 and even i tried on my father laptop with his own account and couldn't sign-in under his account, and i believe this problem is on firefox 50 otherwise i downgrade both laptop to firefox 49.0.2 everything is working and the thing is we have both separate account and my dad is different than mine and right now both Sign-in sync is working otherwise i had no luck with firefox v50 so if i were you just downgrade your firex to 49.02 until firefox genius department figure this S@#t out

Firefox 50.0.1 its same i cannot signin im stick to firefox 49.0.2

Would you do this please: 3-bar menu > Options > Privacy > History > Make sure you set it to   Remember History   (and definately not to   Never Remember History)

What the HELL?! I changed my Privacy History setting from "Never Remember History" to "Remember" and now the sync Account sign-in is Working!! , and I want to know is this a bug ? Are Firefox team going to Fix this problem? Because im not comfortable to change my privacy history setting to "Remember" , please guys fix this problem. thank you

Yes that is a Bug and it is going to be fixed - hopefully soon.