CORS post with preflight request

Question

I\'m trying to upload files to a service on a different domain using CORS, but they keep failing due to the origin being denied. As far as I can see the correct headers are bein

Answer 1

It's little late, but looking at your info it shows the pre-flight CORS check works OK, it's just the actual (2nd) CORS request where the response gets blocked by the browser.

It's a pity you didn't include the response for the actual (2nd) CORS request because that might have contained the clue for the response rejection. My suspicion is that although the pre-flight response correctly contains the header:

Access-Control-Allow-Origin:*

... your actual (2nd) response might not have contained that header, in which case the browser correctly rejects the response. If my assumption is true, the solution would be to just include this header also in the actual (non pre-flight) response.