Instagram webhook not triggering - Stack Overflow

I am trying to receive Instagram webhook notifications for my own Instagram account. I have done all the followings as stated in the documentation (). However, not receiving any webhook notifications at all.

1. The endpoint is registered in Meta dashboard and tested (which worked).
2. My own instagram account is integrated in Meta dashboard and access token is generated with permissions such as instagram_business_basic and instagram_business_manage_comments.
3. Subscribed to comments and mentions fields. (below is the result of getting /me)

{"id":"id","username":"username","subscribed_apps":{"data":[{"id":"id","subscribed_fields":["mentions","comments","messages"]}]}}

4. Live mode is enabled
5. Added the instagram account above as a test user
6. Business verification is passed

After doing all these and mentioning above's Instagram account from a different instagram user on a specific media is not working (any other webhook notifications are not working, just to be clear). The test requests from the dashboard are working fine.

Am I missing something ... ? I am stuck on this issue for sometime now and any help would be much appreciated. From my understanding, standard access level is all I need since I only want notifications for my own instagram account.