Error getting response; org.apache.http.NoHttpResponseException: The target server failed to respond

Soap Version: 5.0.0 (Free version) 

Each time i submit a request to a specified endpoint which is outside of my corporate network im receiving: 

'Error getting response; org.apache.http.NoHttpResponseException: The target server failed to respond'

 I can run the exact same request using another computer, same network and it works correctly. 

It's like something is blocking the requests from being made when going outside the network. An internal endpoint works everytime. 

Any ideas?