Can you please go to Settings>Channel integration>Edit Channel details and click on Test.
This error could be returned due to the eBay token expiration, in case you see the expiration message, please renew the token and create the listing again.
I am trying to list products on ebay es, fr, it and ie but this error pops up everyt time for 3 days. "The remote server returned an error: (404) Not Found."
Can I get some help here please?