Not signed in

What it means

No session cookie, or one that is no longer valid. The response does not say which — an expired session and a fabricated one give the same answer, because distinguishing them tells an attacker whether a stolen identifier was ever real.

What to do

Sign in again at POST /api/v1/auth/sign-in, then complete the TOTP challenge. Staff sessions require both.

The response

{
  "type": "https://casanova.realty/problems/unauthenticated",
  "title": "Not signed in",
  "status": 401,
  "detail": "A sentence about this particular occurrence.",
  "instance": "/api/v1/properties/some-listing"
}

Content type is application/problem+json. Match on type, not on title — the title is prose and may be rewritten.