it is possible for someone at Shopify to investigate why the requests to your endpoint have stopped. You can contact Shopify Support and provide them with the details of your fulfillment service and the issue you are experiencing.
You can contact Shopify Support through the Shopify Help Center by selecting "Contact support" and providing your store's details and a description of the issue you are experiencing. You may also want to include any relevant logs or error messages from your endpoint to help with the investigation.
Once you have submitted a support request, a member of the Shopify support team will review your issue and provide assistance as needed.