요약
A condition in the request headers evaluated to false on the server.
언제 발생하나
Returned when If-Match / If-Unmodified-Since preconditions are not met.
흔한 원인
- Resource changed since the ETag was fetched
- Stale If-Match / If-Unmodified-Since value
해결 방법
- Refetch the current ETag and retry
- Remove the failing precondition if not needed