This error occurs when the currency for the item you are listing from SynCommerce, is different from the currency on the site you are publishing it to.
When you encounter such an error, double check to ensure your eBay store connected to SynCommerce, is in the same eBay site and currency as the one you are publishing to. If the site and currency is different, simply change the site and currency to the correct one to match the eBay store you are publishing to.
Follow these simple steps to check your site and currency, as well as update it accordingly if needed.
STEP 1: Go to the Channels page
STEP 2: Click to edit store details.
On the channels page, click the settings icon on the connected store you want to edit, then select "Edit details".
STEP 3: Confirm eBay site and currency, and update if necessary.
Contact support at firstname.lastname@example.org for any further help.