How do I resolve an "ERROR 303" from grbgetkey?

If grbgetkey produces a message that looks like this:

  ERROR 303: hostname mymachine.mydomain (234.28.234.144) not recognized as
  belonging to an academic domain

it means your domain isn't on our academic domain list.

• Please make sure you are connected to your university network. If you are validating a home machine and the university provides a VPN, please connect to it before retrieving your license.
• If you are having trouble validating your license through a VPN, note that some VPNs are configured to use split tunneling, where traffic to public internet sites is routed through your ISP. You should ask your network administrator whether the VPN can be configured to route traffic to gurobi.com through the private network.
• If traffic gets split up via split tunneling and not all your internet traffic is directed through the VPN connection, you can try to force the traffic to not be split:
  • https://superuser.com/questions/1021371/in-windows-10-how-do-you-ensure-all-traffic-goes-through-vpn
  • https://apple.stackexchange.com/questions/144572/where-is-the-send-all-traffic-over-vpn-connection-setting-in-osx-10-9-maverick

For more information., please see the section "Academic validation" in the Quick Start Guides:

• Windows
• Linux
• MacOS

 If you are still receiving a 303 error, please submit a new request with "Type of Issue" as "License key" and "Type of request" as "Academic validation" and attach a screenshot. Someone from our support team will be happy to help you.

Example of a screenshot: