Facebook log in keep redirecting in iOS

Question

I have an Unity application using Facebook SDK for user to link their account. Everything works in Android. But in iOS, the login page keep redirecting to the previous page which asking me to login even I press "Continue".

https://youtu.be/nGs8jiaI24s

I have found that there is a post asking the same question. But the solution does not work for me.

Unity Facebook SDK is keeping on asking me to confirm login every time I login to my game

In my case, FB.IsLoggedIn return false so loginWithReadPermission is still being called and user fall in the loop between login and continue.

Are there any method to solve it, or at least get the error message?