Currently You are Limited to X Listings. This will be Increased as You Complete More Sales.
An account on Mercari.com or eBay needs to complete a certain amount of sales to be capable of posting more than X (100, 500, etc) listings to Mercari.
"Currently you are limited to X (100, 500, etc) listings. This will be increased as you complete more sales." error is related to Mercari.com or eBay. You can get your limit increased when you make more sales on Mercari.com or eBay.