Check WinHTTP proxy settings
By default, the Windows Agent uses WinHTTP and Windows includes an WinHTTP Proxy Configuration Tool you can use to determine if the computer's WinHTTP connection is direct or through a proxy.
For example, if the Windows Agent was setup to connect directly to the internet, but a connection cannot be established. When you run the tool it may show that the computer is connecting through a proxy and after adding the proxy settings in the Windows Agent a connection is established.
The version of the WinHTTP Proxy Configuration Tool depends on the version of Windows installed on the computer.
Use the netsh command to show the proxy settings open a command prompt and enter netsh winhttp show proxy.
This returns the method used by WinHTTP to connect:
C:\>netsh winhttp show proxy
Current WinHTTP proxy settings: Direct access (no proxy server).