WNS(Windows Notification Service) is not reachable

Problem

Trying to reach a managed mobile device, fails and you get the error message "WNS is not reachable"

Cause

This could happen due to various reasons such as 

• Port Blocked
• Proxy not configured

Resolution

Port Blocked:

Ensure that the following ports are open on the Mobile Device Manager Plus proxy/firewall:

HTTPS ports 9383 and 8383 should be opened, this will allow the Mobile Device Manager Plus Server to communicate with the MDM Agent.
TCP port # 443 should be opened, this will allow the Mobile Device Manager Plus Server to communicate with WNS.
Ensure that the Mobile Device Manager Plus server has permission to reach https://login.live.com & https://*.notify.windows.com

Proxy Not Configured:

If the network in which Mobile Device Manager Plus server is installed has a proxy, ensure that the proxy settings are configured. Verify the user name and the password for proxy authentication, so that the server can reach WNS.

Applies to: Scanning the mobile device, Distributing Apps, Associating Profiles

Keywords: MDM scanning, Associating profiles, WNS, Mobile Device Management.