Angular keeps aborting OPTION request

I'm building small rest application: express backend, jwt auth. cors middleware

From another restful client all works fine.

OPTION response

Status Code: 204 No Content
Access-Control-Allow-Methods: GET,HEAD,PUT,PATCH,POST,DELETE
Access-Control-Allow-Origin: *
Connection: keep-alive
Date: Sat, 14 Mar 2015 17:19:48 GMT
Vary: Origin
x-powered-by: Express

POST response

Status Code: 200 OK
Access-Control-Allow-Origin: *
Connection: keep-alive
Content-Length: 44
Content-Type: application/json; charset=utf-8
Date: Sat, 14 Mar 2015 17:21:14 GMT
Vary: X-HTTP-Method-Override, Origin
x-powered-by: Express

but from my angular app all OPTION req aborted. There's nothing special in my angular code, just form sending an object.

Request headers: Request URL:http://localhost/signup

Access-Control-Request-Headers:accept, content-type
Access-Control-Request-Method:POST
Origin:http://localhost:3111
Referer:http://localhost:3111/
User-Agent:Mozilla/5.0 (Windows NT 6.3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36