unlink twitter: firebase ios swift

Question

I am trying to allow the user to unlink their twitter account from the edit profile page in my iOS app, but I keep getting this error:

User was not linked to an account with the given provider.

Even though when I check the email in the console and compare to firebase dashboard, and the email is indeed linked to twitter. I tried looking at the firebase docs but don't see a list of what to put for the providerString anywhere. I tried "Twitter", "twitter" , "TwitterProvider" and get the same result.

here is my code:

Auth.auth().currentUser?.unlink(fromProvider: "Twitter", 
    completion: { (data,error) in
            if let data = data {
                debugPrint("data \(data)")
            } else {
                debugPrint("whats happening here?: \(error?.localizedDescription)")
                debugPrint(Auth.auth().currentUser?.email!)
            }
        })

If I attempt to link twitter again, I get:

"[ERROR_PROVIDER_ALREADY_LINKED] - User can only be linked to one identity for the given provider." UserInfo={NSLocalizedDescription=[ERROR_PROVIDER_ALREADY_LINKED] - User can only be linked to one identity for the given provider., error_name=ERROR_PROVIDER_ALREADY_LINKED}

Answer 1

I believe it should be the providerId twitter.com: Auth.auth().currentUser?.unlink(fromProvider: "twitter.com", ...