431 Request Header Fields Too Large
One header, or all headers together, are too large.
What it means
Often caused by oversized cookies or tokens.
What your client should do
Trim cookies or headers and resend.
Should you retry?
Only after you change the request.
Try it
The free practice API returns this status on demand, with the headers a well-behaved API would send. Call GET /api/play/status/431 from Endpoint Client and open the Explain tab.
Defined in RFC 6585. All status codes and headers