M2E error - "This Listing is a duplicate of your item: [item name]..."

Problem

Here is the full error that I'm receiving from M2E.

"This Listing is a duplicate of your item: [item name]. Under the Duplicate Listing policy, sellers can't have multiple Fixed Price listings, multiple Auction-style (with the Buy It Now option) listings, or in both the Fixed Price and Auction-style (with the Buy It Now option) listings for identical items at the same time. We recommend you create a multiple quantity Fixed Price listing to sell identical items."