Unknown Signer – SignatureAPI Docs

What Happened

A place in the document references a recipient_key that does not match any recipient in the envelope.

The response includes a detail property with more information about this error.

Check the detail property to identify which recipient_key is unrecognized.
Ensure the envelope includes a recipient of type signer with a key that matches every recipient_key used in the document’s places.
Keys are case-sensitive. Verify that spelling and casing match exactly between the recipient’s key and the place’s recipient_key.