Some users -- but by no means all -- seem to be having the same problem. The site is not actually down, though once you start to list and encounter this problem you may have problems connecting to the site for many minutes.
If you are using a VPN, try disabling it and then clearing your browser cache and deleting eBay cookies 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...
