Check that you have configured and saved the shipping parameters with at least one domestic shipping / shipping service.
If so, make sure that the product that generate the error does not have specific carriers configured in Prestashop (in the Product / Shipping tab). –
so, make sure that at least one of the Fastbay-configured carrier is selected and has a valid range in weight / price compatible with the product you intend to synchronize.
If the error persists, check that you have not entered duplicate eBay carriers in the module .Some configurations of this kind may not be accepted by eBay, making it necessary to differentiate the shipping service for each
carrier configured in the module (eg – if you have set “Other 24-hour courier” twice, change one of the two values with a similar courier, eg “Other Courier 48 hours “).