This error means you need to check that the ports are open. Port 80 if you are on 9.8 pre-patch or port 443 if you are on any of the newer releases.
To test if the network is blocking access, try to ping and telnet to the license server:
telnet 188.8.131.52 443 ***Assuming you have the telnet utility installed
If either or both fail then we know this is a network issue and you will need your network team to unblock that port.
If unblocking the port is not possible, then you will have to use an offline license. The process to obtain an offline license is when you launch erwin DM and enter the license code, make sure to check the box "Do Offline Activation", then send us the Activation certificate, which we will use to generate your license.