An error getting when i try to send a message to microsoft teams channel by using Graph API

Question

Hi team,

I have created a console application in .NET core. I have installed Microsoft Graph into this application by using NuGet Packet manager. I got an error ("UnAuthorized") when I try to send a message to Microsoft teams channel . I mentioned by sample code below,

AzureGraphAuthConfig config = AzureGraphAuthConfig.ReadFromJsonFile("appsettings.json");
IConfidentialClientApplication confidentialClientApplication = ConfidentialClientApplicationBuilder
.Create(config.GraphClientId)
.WithTenantId(config.GraphTenant)
.WithClientSecret(config.GraphClientSecret)
.Build();

            ClientCredentialProvider authProvider = new ClientCredentialProvider(confidentialClientApplication);
            graphClient = new GraphServiceClient(authProvider);


            var chatMessage = new ChatMessage
            {
                Body = new ItemBody
                {
                    Content = "Hello Team"
                }
            };

            var res = await graphClient.Teams[teamId].Channels[channelId].Messages.Request().AddAsync(chatMessage);

---

Getting an error When I execute this code. But working fine from Graph explorer.
Could you please suggest a proper solution for this?

THANKS

Answer 1

Make sure that your application is presenting a valid access token to Microsoft Graph as part of the request. This error often means that the access token may be missing in the HTTP authenticate request header or that the token is invalid or has expired. We strongly recommend that you use the Microsoft Authentication Library (MSAL) for access token acquisition. Additionally this error may occur, if you try to use a delegated access token granted to a personal Microsoft account, to access an API that only supports work or school accounts (organizational accounts).

Reference document-https://learn.microsoft.com/en-us/graph/resolve-auth-errors#401-unauthorized-error-is-your-token-valid