1、查看mapi/http的虚拟目录配置情况

      Get-MapiVirtualDirectory | fl auth   

     在iis中回收MSExchangeAutodiscoverAppPool

2、修改注册表

     [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\AutoDiscover]

      “ExcludeHttpsRootDomain”=dword:00000001

      “ExcludeHttpsAutoDiscoverDomain”=dword:00000001

参考链接:​​https://www.systoolsgroup.com/updates/outlook-takes-long-time-to-connect-exchange-server/​​  

                 ​​https://social.technet.microsoft.com/Forums/Azure/zh-CN/945c4539-380f-4cc1-b89a-c786cfc59dcc/outlook27491223123683025509?forum=exchangeserverzhchs​