like below fixes the issue Solved this! Originally I just transferred my app from the old console and was using 'signInWithEmail'. I just deleted my app on the new Firebase console, started a new one, and used FIREmailPasswordAuthProvider and 'signInWithCredential' instead and everything seems to be working now.
How to link Phone with Email/Password Authentication?
I hope this helps you . I am trying to create a flutter app in which after creating a user with email/ password they are saved in the firebase then the user enters his phone number on which OTP is sent and the user is logged in after verification. my problem is that when both of these steps are completed firebase is creating two separate accounts one with email other with the phone. Please tell me how can I create a Single account with Both Email/Password and Phone. I also want to login with both Email/Password or Phone. Or any other way to create a user with email/password and Phone.