How to enable CORS in ASP.NET Core

Question

I am trying to enable cross origin resources sharing on my ASP.NET Core Web API, but I am stuck.

The EnableCors attribute accepts policyName

Answer 1

If you are hosting on IIS, one possible reason is you are getting this is because IIS is blocking OPTIONS verb. I spent almost an hour because of this:

One telltale indication is you are getting 404 error during OPTIONS request.

To fix this, you need to explicitly tell IIS not to block OPTIONS request.

Go to Request Filtering:

Make sure OPTIONS is allowed:

Or, just create a web.config with the following setting: