This error means Etsy found no domestic service in the product's shipping profile that accepts the weight or dimensions Shuttle sent. It can appear when you transfer a product to Etsy, and also when Shuttle updates a listing that is already on Etsy.
Why it happens
The weight is over every domestic limit. Each domestic service in an Etsy shipping profile has its own weight limit, so a profile that works for lighter products can still fail here. Shuttle sends the weight of the product's first variant in Shopify.
The dimensions are over every domestic limit. Each domestic service also has its own limits for a product's dimensions. Shuttle sends your Length, Width and Height metafields, or your default dimensions when those are empty.
The product has no weight in Shopify. Shuttle then uses the Weight metafield if you named one, otherwise your Default weight. When Shuttle transfers a product on a calculated shipping profile with neither, it sends a fallback weight. That is 1 oz if your weight unit is pounds or ounces, or 30 g if it is grams or kilograms. That weight is small, so this error more often comes from a heavy product or a profile whose domestic services have low weight limits.
A unit is wrong. Default weight and Weight metafield values are read in the Weight unit you chose. The default dimensions and Length, Width and Height metafield values are read in the Dimensions unit you chose. A metafield of the Dimension or Weight type stores its own unit, so Shuttle converts it automatically.
The product gets a different profile than you expect. Products follow your shipping profile matches, or your collection mapping if your Shopify store uses market-driven shipping. Unmatched products get your Etsy default profile.
How to fix it
In Shopify, check the weight of the product's first variant and the product's Length, Width and Height metafields. Correct them if they are wrong.
If the product has no weight or dimensions in Shopify, open Settings > Products > General > Shopify metafields. If a Weight, Length, Width or Height metafield is named, fill it in on the product. If not, set Default weight, Default length, Default width and Default height under Settings > Products > Shopify → Etsy > Dimensions & Weight.
On the Dimensions & Weight card, check Default weight, Default length, Default width and Default height. Check that Weight unit and Dimensions unit match the numbers you entered. A metafield of the Dimension or Weight type stores its own unit, so Shuttle converts it automatically.
Go to Settings > Catalog Mapping > Shipping Profiles and check the Etsy default and Match shipping profiles. If that page says your Shopify store moved to market-driven shipping, check Settings > Catalog Mapping > Shipping → Collections instead.
In Etsy, open that shipping profile. Raise a domestic service's limit, or add a service that covers the weight and dimensions.
Transfer the product again, or update it if it is already on Etsy.
Still seeing it?
If the weight and dimensions are correct and a domestic service covers them, contact support. Tell us the product name and the shipping profile it should use.