Facebook Graph API not fetching details of Gated Posts (Targeted Posts)

Question

I am trying to fetch the information of all the posts published/scheduled on my own facebook page. For gated or posts which are targeted to specific country/language/age it shows the following error. It used to work before now, recently I created a new facebook app 2.6 version. Just wondering if that has caused the problem. Other posts are being fetched without any issues whereas facing problems with gated posts.

This is the error message:

Unsupported get request. Object with ID 'xxxxxxxxxxxxxxxxxxxxxx' does not exist, cannot be loaded due to missing permissions, or does not support this operation. Please read the Graph API documentation at https://developers.facebook.com/docs/graph-api", "type": "GraphMethodException", "code": 100,