When attempting to disconnect a user from the Administration perspective -> User Management -> Connections, an error like this may pop up:
'USERNAME/DEPARTMENT': Access denied
Turning on SECURITY_AUDIT_FAILURE in UC_CLIENT_SETTINGS shows messages like:
Automation Engine 21.0, V24
The minimum requirements for a user to be able to disconnect a user based on username like USERNAME/DEPARTMENT are:
Privileges: Access to Administration
Authorizations:
Grp. [1-9]
Type: USER
Name: USERNAME/DEPARTMENT
C-Cancel: checked
This is also true for the ApplicationInterface and for the REST API in 24.4 with the /{client_id}/system/users/{user_name}/connections DELETE function.