ملخص
A condition in the request headers evaluated to false on the server.
متى يحدث
Returned when If-Match / If-Unmodified-Since preconditions are not met.
الأسباب الشائعة
- Resource changed since the ETag was fetched
- Stale If-Match / If-Unmodified-Since value
طريقة الحل
- Refetch the current ETag and retry
- Remove the failing precondition if not needed