AWS cognito does not generate tokens when run from a serverlet

I am trying to get amazon cognito to work. If I run the code to generate a login token from a standalone java program it works.

public class cognito extends HttpServlet
{


public static void main(String[] args) throws Exception {

AWSCredentials credentials = new BasicAWSCredentials("*******", "********");

AmazonCognitoIdentityClient client =
new AmazonCognitoIdentityClient(credentials);
client.setRegion(Region.getRegion(Regions.EU_WEST_1)); 
GetOpenIdTokenForDeveloperIdentityRequest tokenRequest =
new GetOpenIdTokenForDeveloperIdentityRequest();
tokenRequest.setIdentityPoolId("*************");
HashMap<String, String> map = new HashMap<String, String>();

//Key -> Developer Provider Name used when creating the identity pool
//Value -> Unique identifier of the user in your <u>backend</u>
map.put("test", "AmazonCognitoIdentity");

//Duration of the generated OpenID Connect Token
tokenRequest.setLogins(map);
tokenRequest.setTokenDuration(1000l);

GetOpenIdTokenForDeveloperIdentityResult result = client
.getOpenIdTokenForDeveloperIdentity(tokenRequest);
String identityId = result.getIdentityId();
String token = result.getToken();

System.out.println("id = " + identityId + "  token = " + token);


} 

}

However when I run this code from a servlet on a redhat linux server, it always times out. Any suggestion would be helpful