Variation Specifics provided do not match the Variation Specifics on the item

The error indicates that there is a mismatch between the Variation Specifics that you are attempting to update and the Variation Specifics of the actual Item listed on eBay. 

For example, you are selling a shirt that has two variations: Color and Size. If you attempt to update the product with the variation specifics ‘Medium Sise’ and ‘Bright Yellow’ while the actual Item is listed with the variation specifics ‘Medium’ and ‘Yellow,’ the error will prevent the update. 

To resolve the error, you have to check the variation specifics of your Magento product and make sure that they match the variation specifics of the actual Item listed on eBay. You can try to Revise the product once you update the variation specifics to match the ones on the channel.