Need help in integrating favourite collection

I am trying to integrate favourite collection in our product. I have a service account 'developer@simpplr.com' to which I am connected where there is 'Simpplr zeus POC' app is created. I have other user account 'box1@simpplr.com' which is authorized to access the 'Simpplr zeus POC' app and files from service account. I have granted all the permissions as well that I found in App configuration(added attchment).

I have added some items/files in favourite collection in box1 user UI portal. Now I am trying to get the favourite collection using access-token(developer token) from box1 user account but I am receiving [] (empty) response. Is there anything I am missing? Any help is appreciated.

CURL I am using is from documentation is as below:

curl --location --request GET 'https://api.box.com/2.0/collections/:favourite_collection_id/items' \

--header 'Authorization: Bearer <access_token>' \

--header 'Cookie: box_visitor_id=620cd0fef00c02.46213116'

Postman API response for the reference: