现象
打开Exchange Management shell报错不能连接某个服务器：WS-management服务无法处理该请求，已经超过系统的负载配额，以较慢速率发送将来的请求或提高系统配额。（The WS-Management Service cannot process the request. The User load quota of xxxxxxxx requests per 60 seconds has been exceeded. Send future requests at a slower rate or raise the quota for this user）
解决方法
recycling the applicationpool MSExchangePowerShellAppPool in IIS
登录不能连接的Exchange服务器，打开IIS管理器，选择“应用程序池”中MSExchangePosershellAppPool，右击“回收”
