why i 401 errors joining dynamics crm metadata service?

i am joining crm idea retrieving list picklist values. growth accessory i am operative underneath possess login name works fine. exam server, formula executes underneath network use account. connects crm web use all great. connects metadata use i 401 unapproved messages.

this initial i have used metadata use i am anticipating someone tell me since i error. tie configured controlling formula next disaster happens try collect picklist data.

crmauthenticationtoken token = new crmauthenticationtoken();
token.organizationname = config.appsettings.settings["crmtargetorganisation"].value;
token.authenticationtype = 0;

metadataservice use = new metadataservice();
service.credentials = system.net.credentialcache.defaultcredentials;
service.url = config.appsettings.settings["crmmetadataserviceurl"].value;
service.crmauthenticationtokenvalue = token;
service.unsafeauthenticatedconnectionsharing = true;