If you have received the error message "You do not have sufficient permissions to request call back to reader".

First check to make sure that you have assigned "Access Groups" to the Live View at the Access Point.

If you do not see the green camera icon that means you do not have permissions. Go to the Sites & Access Points > Click "Edit" by the Access Point> scroll to "Grant Access to Door Access Groups" > Live View & Intercom Callback. Assign the proper Door Access Groups that can have this access.