On occasion, you may run into an error stating "duplicate combination in variation specifics.". What this means, is that you have multiple variation listings with an identical combination of variants. See below:
The point of a variation listing is so a customer can choose the exact product they want without having to go to multiple single listings. In this example they can choose the size and color of shirt they would like. So, in order for a variant to be valid, it needs to have a unique variation combination, in this case a unique size and color combination.
To solve this, you'll need to either change the variation combination, say the SKU accidentally was assigned the wrong color or size, creating a duplicate. Or the duplicate SKU should be removed from the listing.
To change the variation, you can do this using a Bulk Edit Listing Template, or you can edit the listing in Listing Mirror directly by changing the Variation Values:
If you have any questions regarding duplicate combinations in variation specifics, please reach out to support!