Résumé
A condition in the request headers evaluated to false on the server.
Quand cela se produit
Returned when If-Match / If-Unmodified-Since preconditions are not met.
Causes fréquentes
- Resource changed since the ETag was fetched
- Stale If-Match / If-Unmodified-Since value
Comment résoudre
- Refetch the current ETag and retry
- Remove the failing precondition if not needed
Base dans la spécification