Error selling item on Steam Marketplace

Hello exiles, I have a problem where I can't sell 3 items that I have in my Steam inventory on the Steam Marketplace.

The items are not equipped on any character and I still can't sell them because I always get an error message: Unable to contact the game's item server. It may be down or Steam may be experiencing temporary connectivity issues. Your listing was not created. Please refresh the page and try again.

Can someone help?