This is not necessarily an error: some eBay categories may not have optional / mandatory specifications, so the module may not receive any data and continue to display the warning.

You can check the specifications required by an eBay category at any time by simulating the sale of a product directly from the eBay website in the category of your interest: If the category you selected iin the module no longer exists on eBay, you may fall into the case described here, in which case please update and map the new categories in the tab “Categories” to solve the problem and get the new specifications.