Update Statistic: invocation of cloud script function failed

Hi, I am trying to update an statistic with an Azure Function (which I think it is fine). I don't manage to solve this problem.

This is the azure function, which I can publish without a problem. If I publish another function that only returns the name and time it works fine. The problem is with the request to update the statistic.

Azure function:

namespace FuncionRankingPrueba1
{
    public static class RankingPrueba
    {
        [FunctionName("UpdateRanking")]
        public static async Task<dynamic> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            string name; 
            string time; 
            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = data?.FunctionArgument?.name;
            time = data?.FunctionArgument?.time;
            int timeint=  int.Parse(time);


            var request = new UpdatePlayerStatisticsRequest
            {
                PlayFabId = data.CallerEntityProfile.Lineage.MasterPlayerAccountId,
                Statistics = new List<StatisticUpdate>
            {
                new StatisticUpdate
                {
                    StatisticName = name,
                    Value = timeint
                }
            }
            };
            var apiSettings = new PlayFabApiSettings
            {
                TitleId = data.TitleAuthenticationContext.Id,
                DeveloperSecretKey = Environment.GetEnvironmentVariable("PLAYFAB_DEV_SECRET_KEY", EnvironmentVariableTarget.Process),
            };
            var serverApi = new PlayFabServerInstanceAPI(apiSettings);
            return await serverApi.UpdatePlayerStatisticsAsync(request);
        }
    }
}
 

This is the call from my project, where Prueba3Arnau is the name of the function in Playfab, Level1Times is the statistic name I want to update and time is the integer to pass:

   public void UpdateLeaderBoard()
    {
        Debug.Log("UpdateLead");
        PlayFabCloudScriptAPI.ExecuteFunction(new ExecuteFunctionRequest()
        {
            Entity = new PlayFab.CloudScriptModels.EntityKey()
            {
                Id = PlayFabSettings.staticPlayer.EntityId, 
                Type = PlayFabSettings.staticPlayer.EntityType, 
            },
            FunctionName = "Prueba3Arnau", 
            FunctionParameter = new {name= "Level1Times", time="21"},
            GeneratePlayStreamEvent = false 
        }, (ExecuteFunctionResult result) =>
        {
            Debug.Log($"The {result.FunctionName} function took {result.ExecutionTimeMilliseconds} to complete");
            Debug.Log($"Result: {result.FunctionResult.ToString()}");
        }, (PlayFabError error) =>
        {
            Debug.Log($"Opps Something went wrong: {error.GenerateErrorReport()}");
        });
    }

This is the error

If I go to the second .cs (Assets/PlayFabSDK/Shared...), line 260, this is where it goes:

I don't know if it has something to do with the secret key, a permit that I have to grant or what.

Thanks