Why Do I Get an Access Denied Error when I Activate the Configuration List in SharePoint?
Symptoms
When you try to activate the AgilePoint Configuration List feature, SharePoint Integration in the web application UI for SharePoint 2010, 2013, or 2016 an Access Denied error occurs.
Cause
This error occurs because the Configuration List feature tries to make changes from the content applications (web front ends) to the config application (central admin application). For example, the web.config changes to register safe controls and check if Ajax entries are available.
A security feature implemented in SharePoint 2010, 2013, and 2016 (SPWebService.RemoteAdministratorAccessDenied property in the SharePoint API) explicitly blocks any changes to the objects inheriting from SPPersistedObject in the Microsoft.SharePoint.Administration namespace. This disallows the content web applications to update the configuration database.
This feature can be disabled, but as with any security feature, it is recommended that you proceed with extreme caution and perform thorough testing before doing so.