AgencyReel 2 - Unable to link Facebook business page owned by business manager

This issue commonly occurs because the user's Facebook Profile has not been given Admin access via "Facebook Business Manager" for the Page(s) they are looking to integrate into the app.
To accept app permissions, they must have Administrator access to the Facebook Page(s) they're looking to add, on the "Facebook Business Manager" as well.
So, for all such cases, get admin access permission on ''The Facebook Business Manager'' for such pages.