We recently made an integration using the shopify admin API. We have a test shopify account for this. The webhook creation request I created via Postman through this account returned 200 times successfully with the webhook details. However, while trying to do the same integration for a customer, the webhook details were not returned even though 200 successful returns were made. Additionally, when I sent a request to the endpoint that fetches webhooks, I saw that no webhook was created. I leave a sample screenshot attached. What is the reason of this?
This issue could be related to permissions - ensure that the API key you're using has the necessary permissions to create webhooks on the customer's store.
Also, there might be settings on the customer's store that are preventing the webhook from being created. You might need to check with the customer to ensure there aren't any settings that could be blocking the creation of the webhook.