billing.seats_in_use

What the portals show

The portals translate the code, never the title. The English (en-GB) message, in ICU format with the arguments as placeholders:

{assigned, plural, one {# seat is} other {# seats are}} given out, so the licences cannot go down to {requested}. Remove seats first.

Example response

{
  "type": "https://docs.test.konsolutelab.uk/errors/billing.seats_in_use",
  "title": "…",
  "status": 409,
  "code": "billing.seats_in_use",
  "args": {},
  "traceId": "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01",
  "instance": "/api/v1/…"
}

Handling it

Branch on code, not on title or the status alone, and log traceId. Codes are stable; new codes may appear, so fall back on the HTTP status for a code you do not know. See Handling errors and the list of codes.