500 status code returned from restapi/oauth/token

curl -i  https://platform.devtest.ringcentral.com/restapi/oauth/token -d grant_type=password -d username=XXXXX -d password=XXXX -H 'Authorization: Basic XXXX' -H 'Accept: application/json'  HTTP/1.1 500 Internal Server Error
Server: nginx/1.6.3
Date: Mon, 09 Nov 2015 01:43:36 GMT
Content-Type: application/json; charset=UTF-8
Content-Length: 119
Connection: keep-alive
Set-Cookie: RCRoutingInfo=deleted; Expires=Thu, 01-Jan-1970 00:00:01 GMT; Path=/
RoutingKey: SJC11P01PAS01
X-ERROR-ID: fe3a7b58-9b8c-4f0e-b6ec-71dddf716e73
X-REQUEST-ID: 97625
Content-Language: en
{
  "message" : "Internal Server Error. Consult RC Support.",
  "eventId" : "fe3a7b58-9b8c-4f0e-b6ec-71dddf716e73"
}

Exactly same request was sent before, and returned a meaningful response (access toke, refresh token etc)