EventGrid topic handshake validation fails

Hi Harel, Welcome to MS Q&A

Even if your HTTPS POST is returning a status code 200, there are still a few potential issues that could cause the handshake validation to fail:

1. Response Format: Ensure that the response format is exactly as expected. The response should be a JSON object with the validationResponse property containing the validation code.
2. Content-Type Header: Verify that the Content-Type header of your response is set to application/json.
3. Validation Code: Double-check that the validation code you are returning matches the one sent by Azure Event Grid in the SubscriptionValidationEvent.
4. Network Issues: Ensure there are no network issues or firewalls blocking the request from Azure Event Grid to your endpoint.
5. Endpoint URL: Confirm that the endpoint URL is correct and accessible from the internet.
6. SSL/TLS Configuration: Ensure that your endpoint supports the required SSL/TLS configurations. Azure Event Grid requires HTTPS endpoints with valid SSL certificates.
7. logging: Check your server logs to see if there are any errors or issues when handling the validation request.

By verifying these aspects, you can ensure that your webhook endpoint is correctly handling the validation handshake from Azure Event Grid

For more detailed troubleshooting, you can refer to the following resources:

• Troubleshoot Azure Event Grid subscription validations
• Webhook event delivery
• Authenticate event delivery to event handlers (Azure Event Grid)

Please check and let us know

Thanks
Deepanshu