I use Unity 2021.1.21f1 and I get this error regularly. I did test with earlier versions of Unity and still got it.
I have been google this but it looks like it is an old error that has been fixed??
This is the full message in the console:
PlayFab EditorExtensions: Caught an error:SharedErrorCallbackHTTP/1.1 403 Forbidden #0 GetStacktrace(int) #1 DebugStringToFile(DebugStringToFileData const&) #2 DebugLogHandler_CUSTOM_Internal_Log(LogType, LogOption, ScriptingBackendNativeStringPtrOpaque*, ScriptingBackendNativeObjectPtrOpaque*) #3 (Mono JIT Code) (wrapper managed-to-native) UnityEngine.DebugLogHandler:Internal_Log (UnityEngine.LogType,UnityEngine.LogOption,string,UnityEngine.Object)