Etsy would not create the listing. The Etsy shipping profile Shuttle gave the product has no international shipping option.
Why it happens
The profile has no international option on Etsy. Every product that gets this profile will fail in the same way.
Shuttle used a different profile than you expected. Shuttle picks the profile from your shipping profile matches. It uses your Etsy default when the product's Shopify shipping profile has no match, or when your Shopify store has only one shipping profile. If no Etsy default is selected, Shuttle uses the first profile in your list.
Your Shopify store uses market-driven shipping. In that case Shuttle picks the profile mapped to the first collection the product is in, in the order shown on the Shipping → Collections page. If none of the product's collections are mapped, it uses the Etsy default.
How to fix it
On Etsy, open the shipping profile the product should use. Add an international shipping option and save the profile.
To use a different profile, go to Settings → Catalog Mapping → Shipping Profiles in Shuttle. Under Match shipping profiles, pair the product's Shopify profile with an Etsy profile that ships internationally. Or change the Etsy default under Default shipping profiles. If a profile is missing from the list, click Refresh. Then click Save.
If your store uses market-driven shipping, go to Settings → Catalog Mapping → Shipping → Collections instead. Check the mapping table and the Etsy default under Default shipping, then click Save.
Transfer the product again. See Transfer products between Etsy and Shopify.
Still seeing it?
Contact support if the transfer still fails after the profile has an international option and the right profile is selected in Shuttle. Include the product's name so we can check which profile it was sent with.