question

I have gotten a HelloWorld function running and several API calls work as expected. However, when I call the following code from the client via PlayFab invoke Cloudscript, I get the following error:

{
    "ExecutionTimeMilliseconds": 351,
    "FunctionName": "HelloWorld",
    "FunctionResult": {
        "result": null,
        "customData": null,
        "error": {
            "httpCode": 400,
            "httpStatus": "BadRequest",
            "error": 1001,
            "errorMessage": "master_player_account 3159395147665980277 not found in namespace 1AF050D54886430B",
            "errorDetails": null,
            "requestId": "Failed to Enumerate RequestId. Exception message: Enumeration has not started. Call MoveNext."
        }
    },
    "FunctionResultTooLarge": null,
    "Error": null,
    "Status": 200
}

Bellow is my Azure Function. Please note I made other API calls and environment variables are setup properly.

[FunctionName("HelloWorld")]
        public static async Task<dynamic> HelloWorld(
            [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequestMessage req, ILogger log)
        {
            /* Create the function execution's context through the request */
            var context = await FunctionContext<dynamic>.Create(req);
            var serverApi = new PlayFabServerInstanceAPI(context.ApiSettings, context.AuthenticationContext);
            log.LogInformation("Updated user data for " + context.CurrentPlayerId);
            return await serverApi.UpdateUserDataAsync(new UpdateUserDataRequest
                {
                    PlayFabId = context.CurrentPlayerId,
                    Data = new Dictionary<string, string>() { { "PLS", "haha"} }
            });
  }

Why is this error happening? I am following the same code from the docs. Fuctions V3.