ASSIGN_PROOF_REQUIRED

The assign call needs a proof that the sender is present.

HTTP status	401
Group	Relay path
Retryable	No — sending it again changes nothing
Re-sign	NONE — do not ask the user to sign anything

What happened

A lease is only minted against a presence proof signed with the sender key, or a native-auth token for the sender. A sponsor API key does not prove presence: the assign route does not read X-Api-Key.

What to do

Sign the presence message with the sender key and call assign again.

Extra members

This code carries serverTimeMs in the problem document, on top of the common members.

The problem document

Every error is application/problem+json (RFC 9457) with the same shape:

{
  "type": "https://docs.co-relayer.com/errors/assign-proof-required",
  "title": "The assign call needs a proof that the sender is present.",
  "status": 401,
  "detail": "A sentence about this specific occurrence.",
  "instance": "req_01JB…",
  "code": "ASSIGN_PROOF_REQUIRED",
  "retryable": false,
  "resign": "NONE",
  "hint": "Sign the presence message with the sender key and call assign again."
}

See the error model for what each member means and how to handle unknown codes.