Automating the driver signing using REST API

I got access_token from Access control server and I am trying to use that and get SAS URI but while passing the token in header I am getting HTTP response code as 500.Any help is highly appreciated

Code:
public static void CreateSubmissionMetadata (String access_token) throws ClientProtocolException, IOException{

HttpClient httpClient = HttpClientBuilder.create().build();
String sysdevEndPoint = “https://devicesigningservice.cloudapp.net/api/signing/devices”;
HttpPost request = new HttpPost(sysdevEndPoint);
StringEntity params =new StringEntity(“{"TestHarnessType": "HLK","OSSelections": [{"OS","Windows 7"},{"OS","Windows 8"},{"OS","Windows 8.1"},{"OS","Windows 10"}],"ProductName":"Test Name","InitialUploadFileSize": }”);
request.setHeader(“Content-Type”, “application/json”);
System.out.println(“Sending token ---->”+ access_token);
request.setHeader("Authorization: Bearer ", access_token);
Log.d(“DEBUG”, "HEADERS: " + request.getFirstHeader(“Authorization: Bearer”));
request.setEntity(params);
HttpResponse response = httpClient.execute(request);
System.out.println(response);
Header headers = response.getAllHeaders();
for (Header header : headers) {
System.out.println("Key : " + header.getName()
+ " ,Value : " + header.getValue());
}

output:

2016/07/05 16:27:40:237 EDT [DEBUG] RequestAuthCache - Auth cache not set in the context
2016/07/05 16:27:40:238 EDT [DEBUG] PoolingHttpClientConnectionManager - Connection request: [route: {s}->https://devicesigningservice.cloudapp.net:443][total kept alive: 0; route allocated: 0 of 2; total allocated: 0 of 20]
2016/07/05 16:27:40:238 EDT [DEBUG] PoolingHttpClientConnectionManager - Connection leased: [id: 1][route: {s}->https://devicesigningservice.cloudapp.net:443][total kept alive: 0; route allocated: 1 of 2; total allocated: 1 of 20]
2016/07/05 16:27:40:238 EDT [DEBUG] MainClientExec - Opening connection {s}->https://devicesigningservice.cloudapp.net:443
2016/07/05 16:27:40:240 EDT [DEBUG] DefaultHttpClientConnectionOperator - Connecting to devicesigningservice.cloudapp.net/191.246.47.593:843
2016/07/05 16:27:40:240 EDT [DEBUG] SSLConnectionSocketFactory - Connecting socket to devicesigningservice.cloudapp.net/191.246.47.593:843 with timeout 0
2016/07/05 16:27:40:256 EDT [DEBUG] SSLConnectionSocketFactory - Enabled protocols: [TLSv1, TLSv1.1, TLSv1.2]
2016/07/05 16:27:40:256 EDT [DEBUG] SSLConnectionSocketFactory - Enabled cipher suites:[TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, TLS_RSA_WITH_AES_128_CBC_SHA256, TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256, TLS_DHE_RSA_WITH_AES_128_CBC_SHA256, TLS_DHE_DSS_WITH_AES_128_CBC_SHA256, TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDH_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, TLS_RSA_WITH_AES_128_GCM_SHA256, TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256, TLS_DHE_RSA_WITH_AES_128_GCM_SHA256, TLS_DHE_DSS_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA, TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_RSA_WITH_3DES_EDE_CBC_SHA, TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA, TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA, TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
2016/07/05 16:27:40:256 EDT [DEBUG] SSLConnectionSocketFactory - Starting handshake
2016/07/05 16:27:40:517 EDT [DEBUG] SSLConnectionSocketFactory - Secure session established
2016/07/05 16:27:40:517 EDT [DEBUG] SSLConnectionSocketFactory - negotiated protocol: TLSv1.2
2016/07/05 16:27:40:517 EDT [DEBUG] SSLConnectionSocketFactory - negotiated cipher suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
2016/07/05 16:27:40:517 EDT [DEBUG] SSLConnectionSocketFactory - peer principal: CN=devicesigningservice.cloudapp.net
2016/07/05 16:27:40:517 EDT [DEBUG] SSLConnectionSocketFactory - peer alternative names: [devicesigningservice.cloudapp.net]
2016/07/05 16:27:40:517 EDT [DEBUG] SSLConnectionSocketFactory - issuer principal: CN=Microsoft IT SSL SHA2, OU=Microsoft IT, O=Microsoft Corporation, L=Redmond, ST=Washington, C=US
2016/07/05 16:27:40:518 EDT [DEBUG] DefaultHttpClientConnectionOperator - Connection established 9.82.117.101:65081<->191.246.47.593:843
2016/07/05 16:27:40:518 EDT [DEBUG] MainClientExec - Executing request POST /api/signing/devices HTTP/1.1
2016/07/05 16:27:40:518 EDT [DEBUG] MainClientExec - Proxy auth state: UNCHALLENGED
2016/07/05 16:27:40:518 EDT [DEBUG] headers - http-outgoing-1 >> POST /api/signing/devices HTTP/1.1
2016/07/05 16:27:40:518 EDT [DEBUG] headers - http-outgoing-1 >> Content-Type: application/json
2016/07/05 16:27:40:518 EDT [DEBUG] headers - http-outgoing-1 >> Authorization: Bearer http%3a%2f%2fschemas.microsoft.com%blah%bla
2016/07/05 16:27:40:518 EDT [DEBUG] headers - http-outgoing-1 >> Content-Length: 181
2016/07/05 16:27:40:518 EDT [DEBUG] headers - http-outgoing-1 >> Host: devicesigningservice.cloudapp.net
2016/07/05 16:27:40:519 EDT [DEBUG] headers - http-outgoing-1 >> Connection: Keep-Alive
2016/07/05 16:27:40:519 EDT [DEBUG] headers - http-outgoing-1 >> User-Agent: Apache-HttpClient/4.5.2 (Java/1.8.0_77)
2016/07/05 16:27:40:519 EDT [DEBUG] headers - http-outgoing-1 >> Accept-Encoding: gzip,deflate
2016/07/06 15:14:19:022 EDT [DEBUG] headers - http-outgoing-1 << HTTP/1.1 500 Internal Server Error
2016/07/06 15:14:19:022 EDT [DEBUG] headers - http-outgoing-1 << Cache-Control: no-cache
2016/07/06 15:14:19:022 EDT [DEBUG] headers - http-outgoing-1 << Pragma: no-cache
2016/07/06 15:14:19:022 EDT [DEBUG] headers - http-outgoing-1 << Content-Type: application/json; charset=utf-8
2016/07/06 15:14:19:022 EDT [DEBUG] headers - http-outgoing-1 << Expires: -1
2016/07/06 15:14:19:023 EDT [DEBUG] headers - http-outgoing-1 << Server: Microsoft-IIS/8.5
2016/07/06 15:14:19:023 EDT [DEBUG] headers - http-outgoing-1 << X-AspNet-Version: 4.0.30319
2016/07/06 15:14:19:023 EDT [DEBUG] headers - http-outgoing-1 << X-Powered-By: ASP.NET
2016/07/06 15:14:19:023 EDT [DEBUG] headers - http-outgoing-1 << Date: Wed, 06 Jul 2016 19:14:18 GMT
2016/07/06 15:14:19:023 EDT [DEBUG] headers - http-outgoing-1 << Content-Length: 36
2016/07/06 15:14:19:023 EDT [DEBUG] MainClientExec - Connection can be kept alive indefinitely