Facebook business api instagram accounts endpoint permission issue

We are trying to get an list of Instagram accounts associated to a Facebook business account. The endpoint we are trying to call is: https://graph.facebook.com/v20.0/<business_id>/owned_instagram_accounts?access_token=<access_token>

When using an account which has a developer role in the app the call returns a 200 as expected. But when we use an external account we get the following error:

"error": {     "message": "Unsupported get request. Object with ID '951060758639721' 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,     "error_subcode": 33,     "fbtrace_id": "APTgzDN8PxkeXGu_IZ7HS3q" } 

These are the permissions we have granted and which we all have advanced access from facebook: email, catalog_management, pages_show_list, ads_management, business_management, instagram_basic, pages_read_engagement, public_profile.

Our app is also in live mode.

Does anyone know what we are doing wrong or what we are missing?

We tried everything we know of, tried multiple methods. have requested access to multiple permissions but nothing seems te be working