Some users -- but by no means all -- seem to be having problems listing and getting a "where's all the stuff" error message.
If you are using a VPN, try disabling it before beginning to list. That has worked for some users, apparently.
More suggestions of possible things to try here:
https://community.ebay.com/t5/Report-eBay-Technical-Issues/30-Days-of-listing-I-get-quot-Where-s-all...
