I am only get this screen when I click "Login using OTP":
http://prntscr.com/mo9n55
The black screen shows "Verify Phone number" and "Loading" at the top right of the screen. But nothing happens after that.
Well it seems like phone auth plugin was not updated properly .There is still some old code showing .
Maybe it could caching also .
Please share your ftp credentials in private reply to check this issue further .