I have this problem as well with a new installation. I added Fed Ex with this url https://www.fedex.com/apps/fedextrack/?action=track&tracknumbers=
and checked Add a tracking number to the URL
Please select a provider is returned.
The tracking number is retained with the order, but the status isn’t changed to completed and no message is sent to the customer.
WordPress 5.0.3, Salient 10.0.1, WooCommerce 3.5.5
