How to login to Facebook from another device

 I found this method and wanted to share with you.

First i fail to login by password and i approved via notification from my another already logged in device. It won't let me in and just showing a page with text "Failed to load" or reappearing of the login form.

Second, i tried to add my phone number to receive the OTP via SMS or Whatsapp as 2-factor authentication and also adding one-time backup codes, and yet it still fail when i entered the OTP or the code.

I also tried to logout from my old device and still failed to login from my new device.

Third, i login using my password, then click forget password and selecting login using Google account and it's just keep loading whenever i accepted the permission.

So i selected to receive code from my email, then entered it.

Then it's asking for the code from my Whatsapp OTP as 2-factor authentication i just set, entered it and successfully logged in.

So i thought that Facebook has problem with its security mechanism even though you have password right, or 2-factor authentication right, even the one-time code right.

It needs to prove that you really have the acccess into the account's contacts like email or phone.