Cause
The request has no Authorization: Bearer header with an API key or an access token.
What to do
Obtain a token at /oauth/token or use an API key, and send it in the Authorization header.
application/problem+json
{
"type": "https://masnet.com/developers/errors/unauthorized",
"title": "Not authenticated",
"status": 401,
"detail": "...",
"code": "unauthorized",
"correlation_id": "..."
}