You don't have shipping costs to the USA set up. Until you do, your listings will not show there.
Note that there is a disconnect between measurements for Canada Post parcels and USPS parcels. If they don't match the shipping won't show and the listing won't be on dotCOM.
The way I check, and I am a technodolt so this may not be the best way, is to list then immediately look at my listing.
If the shipping doesn't show, I go to Revise and fiddle with the Canadian dimensions until the US shipping and handling does show.
The differences are in millimetres (did I mention you should use metric? Use metric.) and won't change your costs.
For example, minimum size for Expedited Canada is 10x7x 0.1 cm. For Expedited USA it's 21x4x0.5 cm.
