Yes. You may need to create a separate org level to edit this setting,
if this only applies to certain user accounts.
Content Manager can be configured to allow exceptions ONLY for the
organization-level Approved Senders. User-level Approved Senders are
not allowed.
1) Go to Orgs and Users -> Orgs and search for the organization where
your Content Manager settings are to be configured.
2) Click Edit.
3) Check the check box next to the "Approved Senders" heading.
4) Click Save.
FrankM