I don't know why this thing is happening. I am using android with firebase auth. In sign in method Google and facebook are enable only. And I am allowing only one account per email. I am alos not merging accounts.
What I am doing is :
loged in with facebook. let my email is "xyz@gmail.com" for facebook login.
loged out from facebook.
now login with same email "xyz@gmail.com" but this time i am choosing google login.
now logged out from google
Now when I again login with facebook and email is same i.e. xyz@gmail.com.
It show an error that user is allready register with difrent auth provider
