when sending post request from angular to webapi ?

Question

when sending post request from angular to webapi 

 

http://localhost:31397/oauth/token

 

header:

Content-Type:application/x-www-form-urlencoded

 

body:

username:SuperPowerUser

password:S@12345r

grant_type:password

 

getting  below  error:

 ERROR Response {_body: "{"error":"unsupported_grant_type"}", status: 400, ok: false, statusText: "Bad Request", headers: Headers, …}