Please, I would like to read comments of posts from my Facebook private group and user info (name, id, etc.) who did make the comment. I created an app with permission groups_access_member_info and added it into the Facebook private group but in the facebook API response I can see only my name and ID and I can not see others names or at least their IDs.
I see this (two comments, but I see only my user info "from:" :

But I would like to see something like this as Facebook documents:

The app is in Live mode and I when I want to add it into the private group I see this (there is written "After adding the app into group you will be able: To see post and comments in the group, but not who has written them"):

Can anyoune please help me what can I do wrong? I am concerned about the last screenshot that I added here as there is written ".... but not who has written them" But teh app has permisson groups_access_member_info
Thanks a lot!
EDIT:
Here is what a user grant to our App but his name is not seen in the response:
