Unauthorized error send message from function app to eventgrid when Debugging but OK when run in Azure

Question

I have a function app with a function that sends message to event grid. The function app is RBAC enrolled and authorized. A function in this same function app is subscribed to this event grid topic. When I publish the app to Azure and run it remote it works just fine, but when I run it locally debugging in VS2022 I get unauthorized access to send message. Debuggin in VS2022 works fine for other Azure related stuff we do.

When I execute in debug mode in VS2022 the function app to send data to event grid I get unauthorized error:

//Name of the endpoint of Event grid topic  
    string topicEndpoint = transformAlgoSendRMessage_TopicEP;  
    //Creating client to publish events to eventgrid topic  
    EventGridPublisherClient client = new EventGridPublisherClient(new Uri(topicEndpoint), new DefaultAzureCredential());  
    //Creating a sample event with Subject, Eventtype, dataVersion and data  
    EventGridEvent egEvent = new EventGridEvent("TransformTelemetry", "TransformAlgorithm.broadcastTransform", "1.0", machinePartTransformTelemetry);  
    // Send the event  
      
    try  
    {  
        await client.SendEventAsync(egEvent);  
        if (b_debug_contractor)  
            log.LogInformation("SendRTransformMessage sent transformdata - PosX:" + machinePartTransformTelemetry[1]);  
    }  
    catch (Exception e)  
    {  
        log.LogError("Failed to send SendRTransformMessage. " + e.Message);  
    }  

Unauthorized Error:

Status: 401 (The principal associated with access token presented with the incoming request does not have permission to send data to /subscriptions/mysubscriptionid/resourceGroups/myRG/providers/Microsoft.EventGrid/topics/myfunctionapp. Report '3840bb30-0b52-4869-a3ce-40ef9119ed42:2:11/28/2022 7:44:09 PM (UTC)' to our forums for assistance or raise a support ticket.)  
[2022-11-28T19:44:07.324Z] ErrorCode: Unauthorized  
[2022-11-28T19:44:07.324Z]  
[2022-11-28T19:44:07.324Z] Content:  
[2022-11-28T19:44:07.325Z] {  
[2022-11-28T19:44:07.325Z]     "error": {  
[2022-11-28T19:44:07.326Z]         "code": "Unauthorized",  
[2022-11-28T19:44:07.326Z]         "message": "The principal associated with access token presented with the incoming request does not have permission to send data to /subscriptions/mysubscriptionid/resourceGroups/myRG/providers/Microsoft.EventGrid/topics/myfunctionapp. Report '3840bb30-0b52-4869-a3ce-40ef9119ed42:2:11/28/2022 7:44:09 PM (UTC)' to our forums for assistance or raise a support ticket.",  
[2022-11-28T19:44:07.327Z]         "details": [{  
[2022-11-28T19:44:07.327Z]             "code": "Unauthorized",  
[2022-11-28T19:44:07.328Z]             "message": "The principal associated with access token presented with the incoming request does not have permission to send data to /subscriptions/mysubscriptionid/resourceGroups/myRG/providers/Microsoft.EventGrid/topics/myfunctionapp. Report '3840bb30-0b52-4869-a3ce-40ef9119ed42:2:11/28/2022 7:44:09 PM (UTC)' to our forums for assistance or raise a support ticket."  
[2022-11-28T19:44:07.328Z]     }]  
[2022-11-28T19:44:07.329Z]   }  
[2022-11-28T19:44:07.329Z] }  
[2022-11-28T19:44:07.330Z]  
[2022-11-28T19:44:07.330Z] Headers:  
[2022-11-28T19:44:07.330Z] Server: Microsoft-HTTPAPI/2.0  
[2022-11-28T19:44:07.331Z] Strict-Transport-Security: REDACTED  
[2022-11-28T19:44:07.331Z] x-ms-request-id: 3840bb30-0b52-4869-a3ce-40ef9119ed42  
[2022-11-28T19:44:07.332Z] Date: Mon, 28 Nov 2022 19:44:08 GMT  
[2022-11-28T19:44:07.332Z] Content-Length: 941  
[2022-11-28T19:44:07.333Z] Content-Type: application/json; charset=utf-8  

mysubscriptionid is as shown in the function app screen:

I'm on Microsoft Visual Studio Community 2022 (64-bit) - Current Version 17.4.1

Answer 1

The exception was caused by a log statement in the try statement, irrelevant to send to eventgrid, I can't tell how this stopped from being authorized, now it works.

if (b_debug_contractor)  
        log.LogInformation("SendRTransformMessage sent transformdata - PosX:" + machinePartTransformTelemetry[1]);