[AppInsights][AaronMax] auto instrumentation troubleshooting

Author: AarDavMax

articles/azure-monitor/app/auto-instrumentation-troubleshoot.md

@@ -0,0 +1,46 @@
+---
+title: Troubleshoot Azure Application Insights auto-instrumentation
+description: Troubleshoot auto-instrumentation in Azure Application Insights
+ms.topic: conceptual
+ms.date: 02/28/2022
+---
+
+# Troubleshooting
+
+This article will help you troubleshoot problems with auto-instrumentation in Azure Application Insights.
+
+> [!NOTE]
+>  Auto-instrumentation used to be known as "codeless attach" before October 2021.
+
+## Telemetry data is not reported after enabling auto-instrumentation
+
+Review these common scenarios if you've enabled Azure Application Insights auto-instrumentation for your app service but do not see telemetry data reported.
+
+### The Application Insights SDK was previously installed
+
+Auto-instrumentation will fail for .NET and .NET Core apps if they were already instrumented with the SDK.
+
+Remove the Application Insights SDK if you would like to auto-instrument your app.
+
+### An app was published using an unsupported version of .NET or .NET Core
+
+Verify a supported version of .NET or .NET Core was used to build and publish applications.
+
+Refer to the .NET or .NET core documentation to determine if your version is supported.
+
+ - [Application Monitoring for Azure App Service and ASP.NET](azure-web-apps-net.md#application-monitoring-for-azure-app-service-and-aspnet)
+- [Application Monitoring for Azure App Service and ASP.NET Core](azure-web-apps-net-core.md#application-monitoring-for-azure-app-service-and-aspnet-core)
+
+### A diagnostics library was detected
+
+Auto-instrumentation will fail if it detects the following libraries.
+
+- System.Diagnostics.DiagnosticSource
+- Microsoft.AspNet.TelemetryCorrelation
+- Microsoft.ApplicationInsights
+
+These will need to be removed for auto-instrumentation to succeed.
+
+## Additional help
+
+If you have questions about Azure Application Insights auto-instrumentation, you can post a question in our [Microsoft Q&A question page](/answers/topics/azure-monitor.html).

articles/azure-monitor/toc.yml

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               href: app/status-monitor-v2-api-reference.md
         - name: Java
           href: app/java-on-premises.md
+      - name: Troubleshooting
+      href: auto-instrumentation-troubleshoot.md
     - name: Application Insights SDKs
       items:
       - name: .NET