Adding exception help message

src/client/Microsoft.Identity.Client/Internal/Logger/LoggerHelper.cs

@@ -4,10 +4,13 @@
 using System;
 using System.Globalization;
 using System.IO;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text;
 using Microsoft.Identity.Client.Core;
+using Microsoft.Identity.Client.OAuth2;
 using Microsoft.Identity.Client.PlatformsCommon.Factories;
+using Microsoft.Identity.Client.Utils;
 using Microsoft.IdentityModel.Abstractions;
 
 namespace Microsoft.Identity.Client.Internal.Logger
@@ -110,6 +113,8 @@ internal static string GetPiiScrubbedExceptionDetails(Exception ex)
                 {
                     sb.AppendLine(string.Format(CultureInfo.InvariantCulture, "HTTP StatusCode {0}", msalServiceException.StatusCode));
                     sb.AppendLine(string.Format(CultureInfo.InvariantCulture, "CorrelationId {0}", msalServiceException.CorrelationId));
+                    var aadError = JsonHelper.GetExistingOrEmptyString(JsonHelper.ParseIntoJsonObject(msalServiceException.ResponseBody), OAuth2ResponseBaseClaim.ErrorDescription).Split(':').FirstOrDefault();
+                    sb.AppendLine(string.Format(CultureInfo.InvariantCulture, "AAD Error Code {0}", aadError));
                 }
 
                 if (ex.InnerException != null)
@@ -119,6 +124,8 @@ internal static string GetPiiScrubbedExceptionDetails(Exception ex)
                     sb.AppendLine("=== End of inner exception stack trace ===");
                 }
 
+                sb.AppendLine("To see full exception details, enable Pii Logging. See https://aka.ms/msal-net-logging");
+
                 if (ex.StackTrace != null)
                 {
                     sb.Append(Environment.NewLine + ex.StackTrace);