There is a conflict between the Request Type shown in the Editor Extensions (EE) under Settings, and looking directly at PlayFabSharedSettings.
If you select UnityWww in the EE, it shows Unity Web Request in the shared settings
If you select Unity Web Request in the EE, it shows Custom Http in the shared settings.
Which settings element is displaying the correct value?
Update: This issue has been fixed in lasted PlayFab Unity EdEx: https://aka.ms/PlayFabUnityEdEx.
This is a known issue, in PlayFab EdEx "Unity Www" is actually "Unity Web Request" and "Unity Web Request" is actually "Custom Http".
You can output the request type in Unity, for example:
Debug.Log(PlayFabSettings.RequestType);
10 People are following this question.
