Logic App to Queue - SSL connection could not be established

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05-10-2024

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Logic Apps to Queue: Troubleshooting "SSL Connection Could Not Be Established" Errors

Connecting your Logic App to a queue, like Azure Service Bus, often involves secure communication through SSL/TLS. However, you may encounter the dreaded "SSL connection could not be established" error, leaving you puzzled and your workflow stuck. This article will break down the common causes behind this error and guide you towards solutions.

Scenario:

Imagine you've built a Logic App to send messages to an Azure Service Bus queue. The workflow looks like this:

{
  "definition": {
    "$schema": "https://schema.management.azure.com/schemas/2015-08-01/logic-app-definition.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
      "serviceBusConnectionString": {
        "defaultValue": "<your_connection_string>",
        "type": "string"
      }
    },
    "actions": {
      "Send_message_to_queue": {
        "type": "AzureServiceBusQueue",
        "inputs": {
          "host": {
            "connection": {
              "name": "@parameters('serviceBusConnectionString')"
            }
          },
          "queueName": "MyQueue",
          "message": {
            "body": "Test message"
          }
        },
        "runAfter": {}
      }
    }
  }
}

However, when you run the Logic App, it fails with the error: "SSL connection could not be established." What went wrong?

Possible Causes:

This error typically stems from one of the following:

• Incorrect Connection String: The connection string you're using might be invalid or missing the necessary SSL parameters. It's crucial to ensure the connection string contains the Endpoint=sb://<your_namespace>.servicebus.windows.net/; part followed by SharedAccessKeyName and SharedAccessKey for authentication.
• Trust Issues with SSL Certificate: The SSL certificate used by the Service Bus namespace might not be trusted by your Logic App's environment. This could happen if you're using a self-signed certificate or if there are problems with the certificate chain.
• Network Connectivity Problems: Your Logic App may not have proper network connectivity to the Service Bus namespace due to firewalls or other network restrictions.
• Logic App Runtime Version: Older Logic App runtime versions might have compatibility issues with newer Service Bus security features.

Troubleshooting Steps:

1. Verify the Connection String:

   • Double-check the connection string you're using for any typos or incorrect formatting.
   • Ensure it includes the proper protocol (sb://), namespace, authentication credentials (SharedAccessKeyName and SharedAccessKey), and any necessary SSL options.
   • You can generate a fresh connection string from the Azure portal for your Service Bus namespace to ensure accuracy.

2. Trust the Certificate:

   • If using a self-signed certificate, you'll need to import the certificate into the trusted certificate store of your Logic App's environment.
   • For Azure-managed namespaces, ensure that the certificate chain is complete and the intermediate certificates are trusted.
   • You can use tools like openssl to inspect the certificate chain and identify any issues.

3. Check Network Connectivity:

   • Ensure your Logic App has outbound access to the Service Bus namespace. Verify that any firewalls or other network restrictions are configured correctly.
   • You can use tools like nslookup or ping to test connectivity to the Service Bus endpoint.

4. Update Logic App Runtime:

   • If you're using an older Logic App runtime, consider upgrading to a newer version to improve compatibility with Service Bus features. You can find the runtime version in the Logic App's settings.

Additional Tips:

• Enable Logging: Turn on logging within your Logic App to capture detailed error messages. These logs can help you pinpoint the specific cause of the SSL issue.
• Use the Service Bus Explorer: This tool allows you to visualize your Service Bus namespace and test connectivity without using a Logic App. It can help you quickly identify connection problems.

Conclusion:

The "SSL connection could not be established" error is a common hurdle when working with Logic Apps and queues. By understanding the possible causes and following the troubleshooting steps outlined above, you can resolve this issue and get your Logic App workflow back on track. Remember to always review your connection string, verify certificate trust, ensure proper network connectivity, and consider updating your Logic App runtime to ensure seamless integration with your Azure services.

Resources:

• Azure Service Bus Documentation
• Service Bus Explorer
• Troubleshooting Logic Apps