This is right way to call playfab api in android device, this line of code work perfectly in unity editor not work on android device code mentioned bellow public void Start() { if (string.IsNullOrEmpty(PlayFabSettings.staticSettings.TitleId)) { PlayFabSettings.staticSettings.TitleId = "E1093"; } #if UNITY_ANDROID var request = new LoginWithAndroidDeviceIDRequest { AndroidDeviceId = SystemInfo.deviceUniqueIdentifier, CreateAccount = true, }; PlayFabClientAPI.LoginWithAndroidDeviceID(request, OnLoginSuccess, OnLoginFailure); print("Device UDI " + SystemInfo.deviceUniqueIdentifier); #endif }