What went wrong?
TheCORS request requires preflight, preflighting could not beperformed. There are a couple of reasons why preflighting might fail:
- A cross-site request has previously been performed that already did a preflight, anddoing the preflight again is not permitted. Make sure your code only preflights onceper connection.
- The preflight request suffered any kind of networking error that might ordinarilyoccur.
See also
- CORS errors
- Glossary:CORS
- CORS introduction