Problem: If the Windows Firewall is disabled via an RDP or remote session on a Windows 2008 (and possibly later versions) server, it will disable the network connection.
Cause: The issue is a design implementation by Microsoft, brought about as a result of security concerns.
Resolution: The firewall needs to be disabled locally instead of remotely. If there's no one onsite and both the customer and the technician are accessing it via remote, then it's best not to disable the firewall or both will be unable to reconnect back to it.
The Windows Firewall can be shutdown via the Services Console (services.msc) but the best way to shut it down would be via a command prompt with administrative credentials using the following command: Netsh advfirewall set allprofiles state off