A first chance exception of type 'System.Net.Http.HttpRequestException' occurred in mscorlib.dll

Question

Hi, i am trying to generate the authentication token using AcquireTokenForClient but ending up with Httprequestexception, The code crashes at async method (cca.AcquireTokenForClient(ewsScopes).ExecuteAsync())

below is the code snippet (a well known from MS).

    try  
    {  
     
         // Using Microsoft.Identity.Client 4.22.0  
        var cca = ConfidentialClientApplicationBuilder  
            .Create(sApplicationID )  
            .WithClientSecret(sSecretKey_id)  
            .WithTenantId(sTenantid )  
            .Build();  

        var ewsScopes = new string[] { "https://outlook.office365.com/.default" };  
          
        var authResult = await cca.AcquireTokenForClient(ewsScopes).ExecuteAsync();  

            // Configure the ExchangeService with the access token  
            var ewsClient = new ExchangeService();  
            ewsClient.Url = new Uri("https://outlook.office365.com/EWS/Exchange.asmx");  
            ewsClient.Credentials = new OAuthCredentials(authResult.AccessToken);  
            ewsClient.ImpersonatedUserId =  
                new ImpersonatedUserId(ConnectingIdType.SmtpAddress, "******@xxtest.com");  

            //Include x-anchormailbox header  
            ewsClient.HttpHeaders.Add("X-AnchorMailbox", "******@xxtest.com");  

            // Make an EWS call  
            var folders = ewsClient.FindFolders(WellKnownFolderName.MsgFolderRoot, new FolderView(10));  
            foreach(var folder in folders)  
            {  
                Console.WriteLine("Folder: {folder.DisplayName}");  
            }  
        }  
        catch (MsalException ex)  
        {  
            Console.WriteLine("Error acquiring access token: {ex}");  
        }  
        catch (HttpRequestException   ex)  
        {  
            //Console.WriteLine("Error: {ex}");  
            Console.WriteLine(ex.StackTrace);  

//MessageBox.Show(ex.StackTrace );
}