If you have products that have this error then it is likely that your product has been set up in your eCommerce store as a product with variations/options (eBay call this Multi-SKU) so eBay is expecting a variation but you don't have them.
Check in your eCommerce store for the products to see if there are variations and remove them if they are not required.
For example, often in Shopify the variation is called 'Title'. To resolve this, in your Shopify Store, Go into the product section of one of the products and under 'variants' remove any variations if these products don't come with variations.
You should also double-check in the product page in our system, under Variations.
If there is only one variation, then Variation Name should be empty, ie no options are defined. If you do have options, then at least 2 distinct values should be provided.
Once you have made changes in your eCommerce store go to the dashboard in our system and trigger a refresh by clicking 'Sync Now' from the dashboard so that the updates are sent up to eBay.