[Terran]

If you're not using a router the reason for this is of a completely different nature, it's DNS related:

During startup the engine resolves it's hostname to an IP address. As your internet connection is non-permanent and you have a permanent LAN connection the later one is the first in your local DNS table and therefore selected.

One trick that might work:
- disable your LAN interface
- start the game. It should now register with the internet IP
- reenable the LAN interface