SharePoint 2013里会报8321的错误：
A certificate validation operation took 15011.1412 milliseconds and has exceeded the execution time threshold. If this continues to occur, it may represent a configuration issue. Please see http://go.microsoft.com/fwlink/?LinkId=246987 for more details.
有二种方法，要么安装一个certification，要么禁止它自动更新，下面介绍禁止自动更新：
1. 点击 Start， 输入edit group policy,
2. 双击Computer Configuration –> Windows Settings –> Security Settings –> Public key Policies –> Certificate Path Validation Settings
3. 设置如下：
4. 点击apply，ok。
5. 运行gpupdate /force
引用：http://support.microsoft.com/kb/2625048