Trading API: all POSTs to /ws/api.dll return 503 "Zero size object" on a new production keyset
Summary: craftsfabricsltd is experiencing persistent issues with the Trading API, where all POST requests to /ws/api.dll return a 503 error, specifically a "Service Unavailable - Zero size object" message. This occurs despite successful GET requests and valid POSTs to other endpoints, ruling out issues with the endpoint or credentials. Tests show the problem persists across different configurations, IPs, and environments, including the sandbox. craftsfabricsltd questions if there are restrictions on new production keysets for the Trading API and mentions difficulty in raising a support ticket through AI-Assisted Support.
Production keyset enabled 28 July 2026 after clearing the Marketplace
Account Deletion exemption. Trading has never once succeeded on it. Every POST to https://api.ebay.com/ws/api.dll returns HTTP 503 with an Akamai "Service Unavailable - Zero size object" page. Continuous for 24+ hours. Example: GeteBayOfficialTime, SITEID 3, compat level 1193, valid IAF OAuth token.
What I've ruled out:
- GET on the same URL returns 200 with valid eBay XML (endpoint is up)
- POST /identity/v1/oauth2/token returns 200 (POSTs to the host work)
- REST /sell/fulfillment/v1/order returns 200 with the same token (keyset and grant are valid)
- Fails with no auth headers at all
- Fails identically on sandbox
- Reproduced via curl and python-requests
- Reproduced on three edge IPs, IPv4 and IPv6
- Fails across text/xml, text/xml;charset=utf-8, application/xml
- Fails with and without DEV-NAME/APP-NAME/CERT-NAME
Akamai refs: 15.475ed617.1785333156.32da7882, 15.8abbce17.1785253369.adf96597
Is the Trading API restricted or not enabled by default for newly created production keysets? If so, what's the request process? If not, this looks like a routing fault on the Trading POST path.
Blocks ReviseInventoryStatus and GetMyeBaySelling. REST order reads work.
I could not raise this as a ticket: the AI-Assisted Support tab spins on "Suggested Solution" indefinitely and never creates one.
