Playfab DisplayName is returning null

Question

I'm trying to log the user in and get the username.

When I try to get username on LoginSuccess() via "InfoResultPayload.PlayerProfile.DisplayName" it's returning null. Here's are the login functions:

public void LoginClick()
    {
        var login = new LoginWithPlayFabRequest { Username = Username.text, Password = Password.text,
        InfoRequestParameters = new GetPlayerCombinedInfoRequestParams { GetPlayerProfile = true }
        };
        PlayFabClientAPI.LoginWithPlayFab(login, OnLoginSuccess, OnLoginFailure);
    }
 
 
    private void OnLoginSuccess(LoginResult result)
    {
        //ErrorMessage.text = "";
        //SceneManager.LoadScene(SceneName); // Load Main Scene
        Debug.Log(Username);
        string name = null;
        if(result.InfoResultPayload.PlayerProfile != null)
        {
            name = result.InfoResultPayload.PlayerProfile.DisplayName;
            ErrorMessage.text = name;
            Debug.Log(name);
        }
        
    }

And this is how I registered the user -

public void RegisterClick()
    {
        var register = new RegisterPlayFabUserRequest { Username = Username.text, Email = Email.text, Password = Password.text };
        PlayFabClientAPI.RegisterPlayFabUser(register, OnRegisterSuccess, OnRegisterFailure);
    }
 
 
    private void OnRegisterSuccess(RegisterPlayFabUserResult result)
    {
        ErrorMessage.text = "";
        SceneManager.LoadScene(SceneName); // Load Main Scene
    }

Why am I getting "null" when logging in and how can I get the username of the user?