Invalid signature

HTTP 401   invalid_signature

What it means

The TxG-Key-Id, TxG-Timestamp or TxG-Signature header is missing, or the signature doesn't match the request as TxGold received it.

What to do

If you sign by hand, compare your canonical string with the one in detail: TxGold puts the string it verified there. The usual causes are signing a different body than the one sent (re-serializing the JSON after signing), changing the query string's encoding, or a proxy that rewrites the request. The SDKs sign exactly the bytes they send.

The response

HTTP/1.1 401
Content-Type: application/problem+json

{
  "type": "https://docs.txgold.money/errors/invalid_signature",
  "title": "Invalid signature",
  "status": 401,
  "code": "invalid_signature",
  "detail": "…",
  "requestId": "7219af94e39d"
}

Branch on code, never on title or detail: the code never changes once published, and the text may. Quote requestId to TxGold support. See all errors.