ID3242: The security token could not be authenticated or authorized

public OrganizationServiceProxy ConnectToMsCrm(string UserName, string Password, string SoapOrgServiceUri)
{
try
{
ClientCredentials credentials = new ClientCredentials();
credentials.UserName.UserName = UserName;
credentials.UserName.Password = Password;
Uri serviceUri = new Uri(SoapOrgServiceUri);
OrganizationServiceProxy proxy = new OrganizationServiceProxy(serviceUri, null, credentials, null);
proxy.EnableProxyTypes();

return proxy;
}
catch (Exception ex)
{
LogHelper.Error(typeof(ConnectToMSCrmService), "Error while connectiong to CRM", ex);
return null;
}
}


var proxy = _connectToMsCrmService.ConnectToMsCrm("username", "password", "ipsdev.obeikan.com.sa/.../Organization.svc");

_organizationService = (IOrganizationService)proxy;

Guid userid = ((WhoAmIResponse)_organizationService.Execute(new WhoAmIRequest())).UserId;