Trickster Hollow

The Marketplace store is returning errors. Hello, sorry for asking but i don't know what else to do. I just created a Marketplace store, but im receiving some "error 404" message everytime I try to copy something to the Merchant Outox, and a message like "Marketplace Errors The Marketplace store is returning errors.". I want to know what I am doing wrong. Is there a minimun time for adding stuff that I'm not reading? And if not, can I have some help fixing this problem? Thank you in advance for your time reading this. I hope i can receive help to fix this problem.