What does the VARTA error `session_not_found` mean?

HTTP status: 404  ·  Type: invalid_request_error

What it means

The session (or call) id you supplied is not a value this API ever issued.

What causes it

Raised when a session or call id fails to decode (backend/app/api/v1/_ids.py), from the /v1/sessions/{session_id}... endpoints (backend/app/api/v1/sessions.py) and from GET /v1/calls/{call_id} (backend/app/api/v1/calls.py). That last case is worth noting specifically: call lookups are keyed by the underlying session, so a malformed call_id reports as a missing session, not a missing call.

What to do

Check the id is one this API returned. If you're calling GET /v1/calls/{call_id} and see this code, the call_id itself is malformed — it isn't a signal that the call doesn't exist.