The web app proreception-staging is not sending data to application Insights. Why?

Hello Lars Christiansen
To resolve issues for “Web App not sending data to Application Insights” please try below shared steps as workaround and check if it works.

1. Verify and Update Connection String

• Go to Azure Portal → App Services → Your App (proreception-staging) → Configuration → Application settings.
• Ensure:
  • Present: APPLICATIONINSIGHTS_CONNECTION_STRING (copy from Application Insights → Overview → Connection String).
    • Remove: APPINSIGHTS_INSTRUMENTATIONKEY (legacy key should not be used).
• Click Save and Restart the app. Reference: Microsoft Doc: Connection strings in Application Insights

2. Check Instrumentation Mode

• In App Service → Application Insights:
• If Monitoring = On, rely on autoinstrumentation and avoid conflicting SDK initialization in code.
  • If Monitoring = Off, ensure SDK is initialized in code and reads the connection string. Reference: Enable monitoring in Azure App Service

3. Confirm Network Access

• From Console, run below command

    
    curl -I https://<region>.in.applicationinsights.azure.com/
    
    
  

• If blocked, allow outbound HTTPS (443) to Application Insights endpoints using AzureMonitor service tags. Reference: Azure Monitor network access requirements

4. Validate Telemetry in Logs

• In Application Insights → Logs, run below command

    
    union requests, traces, exceptions, dependencies
    | where timestamp > ago(10m)
    | summarize count() by bin(timestamp, 5m)
  

• If counts > 0 → telemetry is flowing. Reference: Troubleshoot missing telemetry

Most “no data” issues are fixed by:

• Using only the connection string.
• Avoiding SDK/autoinstrumentation conflicts.
• Ensuring outbound connectivity.
• Verifying telemetry in Logs.

Thanks,

Suchitra.