A few ideas:
- Make sure the Eclipse proxy configuration is correct (from Eclipse Preferences). Maybe you should add a proxy bypass to your server host.
- If your server connects in SSL, you should first configure use of SSL, e.g. import server certificate to the JRE used by Eclipse.
- If none of the above solves your issue, you can look into the Eclipse ErrorLog, double click on the "Network Connection Error" message and get more information on what is the nature of the connection error.