Every error code the eBay Sold Listings API returns, what it means, and whether to retry. Errors are never billed.

Errors return an HTTP status and a JSON body with a stable code and a readable message. Only successful requests are billed: every error response, including 5xx, is free.

{ "error": "Too many requests, slow down.", "code": "rate_limited" }

Status	code	Meaning	Retry?
400	`invalid_params`	A parameter is missing or invalid; the message says which	No, fix the request
401	`unauthorized`	Missing or invalid API key	No
402	`quota_exceeded`	Monthly allowance used up, or too small for the batch	No, upgrade or wait for the reset
402	`payment_required`	The last subscription payment failed, so the account is on hold. Never charged	No, update the payment method in Billing. Access resumes automatically once paid
404	`not_found`	Batch job id does not exist for this account	No
409	`conflict`	A batch job is already running, or not finished yet	After the job finishes
429	`rate_limited`	Per-minute limit hit	Yes, after `Retry-After`
502	`upstream_blocked`	eBay temporarily refused this search	Yes, shortly
502	`upstream_error`	Could not reach the data source	Yes, shortly
503	`server_busy`	The data source is busy	Yes, after `Retry-After`
504	`upstream_timeout`	The search took too long	Yes

Same keyword failing again and again.

If one keyword keeps returning upstream_blocked while others work, eBay is refusing that exact search. Try it with fewer words or a different word order, and contact support if it persists.