Troubleshooting in Azure Communication Services

This document will help you troubleshoot issues that you may experience within your Communication Services solution. If you're troubleshooting SMS, you can enable delivery reporting with Event Grid to capture SMS delivery details.

Getting help

We encourage developers to submit questions, suggest features, and report problems as issues. To aid in doing this we have a dedicated support and help options page which lists your options for support.

To help you troubleshoot certain types of issues, you may be asked for any of the following pieces of information:

  • MS-CV ID: This ID is used to troubleshoot calls and messages.
  • Call ID: This ID is used to identify Communication Services calls.
  • SMS message ID: This ID is used to identify SMS messages.
  • Call logs: These logs contain detailed information that can be used to troubleshoot calling and network issues.

Access your MS-CV ID

The MS-CV ID can be accessed by configuring diagnostics in the clientOptions object instance when initializing your SDKs. Diagnostics can be configured for any of the Azure SDKs including Chat, Identity, and VoIP calling.

Client options example

The following code snippets demonstrate diagnostics configuration. When the SDKs are used with diagnostics enabled, diagnostics details will be emitted to the configured event listener:

// 1. Import Azure.Core.Diagnostics
using Azure.Core.Diagnostics;

// 2. Initialize an event source listener instance
using var listener = AzureEventSourceListener.CreateConsoleLogger();
Uri endpoint = new Uri("https://<RESOURCE-NAME>");
var (token, communicationUser) = await GetCommunicationUserAndToken();
CommunicationUserCredential communicationUserCredential = new CommunicationUserCredential(token);

// 3. Setup diagnostic settings
var clientOptions = new ChatClientOptions()
    Diagnostics =
        LoggedHeaderNames = { "*" },
        LoggedQueryParameters = { "*" },
        IsLoggingContentEnabled = true,

// 4. Initialize the ChatClient instance with the clientOptions
ChatClient chatClient = new ChatClient(endpoint, communicationUserCredential, clientOptions);
ChatThreadClient chatThreadClient = await chatClient.CreateChatThreadAsync("Thread Topic", new[] { new ChatThreadMember(communicationUser) });

Access your server call ID

When troubleshooting issues with the Call Automation SDK, like call recording and call management problems, you will need to collect the Server Call ID. This ID can be collected using the getServerCallId method.


callAgent.on('callsUpdated', (e: { added: Call[]; removed: Call[] }): void => {
    e.added.forEach((addedCall) => {
        addedCall.on('stateChanged', (): void => {
            if (addedCall.state === 'Connected') {
       => {
                }).catch(err => {

Access your client call ID

When troubleshooting voice or video calls, you may be asked to provide a call ID. This can be accessed via the id property of the call object:

// `call` is an instance of a call created by `callAgent.startCall` or `callAgent.join` methods

Access your SMS message ID

For SMS issues, you can collect the message ID from the response object.

// Instantiate the SMS client
const smsClient = new SmsClient(connectionString);
async function main() {
  const result = await smsClient.send({
    from: "+18445792722",
    to: ["+1972xxxxxxx"],
    message: "Hello World 👋🏻 via Sms"
  }, {
    enableDeliveryReport: true // Optional parameter
console.log(result); // your message ID will be in the result

Enable and access call logs

The Azure Communication Services Calling SDK relies internally on @azure/logger library to control logging. Use the setLogLevel method from the @azure/logger package to configure the log output:

import { setLogLevel } from '@azure/logger';
const callClient = new CallClient();

You can use AzureLogger to redirect the logging output from Azure SDKs by overriding the AzureLogger.log method: This may be useful if you want to redirect logs to a location other than console.

import { AzureLogger } from '@azure/logger';
// redirect log output
AzureLogger.log = (...args) => {
  console.log(...args); // to console, file, buffer, REST API..

Enable and access call logs (Windows)

When developing for Windows, your logs are stored in .blog files. Note that you can't view the logs directly because they're encrypted.

These can be accessed by looking at where your app is keeping its local data. There are many ways to figure out where a UWP app keeps its local data, the following steps are just one of these ways:

  1. Open a Windows Command Prompt (Windows Key + R)
  2. Type cmd.exe
  3. Type where /r %USERPROFILE%\AppData acs*.blog
  4. Please check if the app ID of your application matches with the one returned by the previous command.
  5. Open the folder with the logs by typing start followed by the path returned by the step 3. For example: start C:\Users\myuser\AppData\Local\Packages\e84000dd-df04-4bbc-bf22-64b8351a9cd9_k2q8b5fxpmbf6
  6. Please attach all the *.blog and *.etl files to your Azure support request.

Calling SDK error codes

The Azure Communication Services Calling SDK uses the following error codes to help you troubleshoot calling issues. These error codes are exposed through the call.callEndReason property after a call ends.

Error code Description Action to take
403 Forbidden / Authentication failure. Ensure that your Communication Services token is valid and not expired.
404 Call not found. Ensure that the number you're calling (or call you're joining) exists.
408 Call controller timed out. Call Controller timed out waiting for protocol messages from user endpoints. Ensure clients are connected and available.
410 Local media stack or media infrastructure error. Ensure that you're using the latest SDK in a supported environment.
430 Unable to deliver message to client application. Ensure that the client application is running and available.
480 Remote client endpoint not registered. Ensure that the remote endpoint is available.
481 Failed to handle incoming call. File a support request through the Azure portal.
487 Call canceled, locally declined, ended due to an endpoint mismatch issue, or failed to generate media offer. Expected behavior.
490, 491, 496, 487, 498 Local endpoint network issues. Check your network.
500, 503, 504 Communication Services infrastructure error. File a support request through the Azure portal.
603 Call globally declined by remote Communication Services participant Expected behavior.

Chat SDK error codes

The Azure Communication Services Chat SDK uses the following error codes to help you troubleshoot chat issues. The error codes are exposed through the error.code property in the error response.

Error code Description Action to take
401 Unauthorized Ensure that your Communication Services token is valid and not expired.
403 Forbidden Ensure that the initiator of the request has access to the resource.
429 Too many requests Ensure that your client-side application handles this scenario in a user-friendly manner. If the error persists please file a support request.
503 Service Unavailable File a support request through the Azure portal.