在另一个线程中使用SSRS Web服务

我使用的代码看起来像这样:

public static void FireAllAsync(string ReportPath)
{
    Hashtable paramValues = new Hashtable();
    ThreadPool.QueueUserWorkItem(new WaitCallback(FireAll), ReportPath);
}

public static void FireAll(object ReportPath)
{

    ReportingService rs = new ReportingService();
    rs.Credentials = System.Net.CredentialCache.DefaultCredentials;

    Subscription[] SubList = rs.ListSubscriptions((string)ReportPath, null);

    foreach (Subscription CurSub in SubList) {
        rs.FireEvent(CurSub.EventType, CurSub.SubscriptionID);
    }

}

召唤 FireAll FireAllAsync 使用Thread失败,出现401错误。我认为证书没有正确传递的问题。即这行代码:

rs.Credentials = System.Net.CredentialCache.DefaultCredentials;

有人知道可能会发生什么吗?