Hi Qian,
Hope your issue has already been resolved by following above recommendations,if still persisting the same issue,kindly check with port which should be open at firewall and also not blocked by any type of antivirus programs as well as by system firewall on the server(If possible try to disable the Antivirus/security for some time to check again).
In resume try to check with any network interruptions / slowness to avoid the issue.For more you could link to SAP Note 180940 - Microsoft QoS support
Hope this will help you.
Regards,