File attachments cannot run just now. 503, retryable. The on-premise service cannot write or read the company's files, has not yet reported that it can, or the file store is down; the detail says which. Every other route is unaffected. Nothing is written.
OPDC API error code
ATTACHMENTS_UNAVAILABLE
HTTP status 503
The API answers with a problem document (RFC 9457) whose type is https://twinn.engineering/errors/attachments-unavailable, and with X-Error-Code: ATTACHMENTS_UNAVAILABLE. Branch on the code, never on the detail text.