I don't believe editing your HOSTS file will fix anything. That's generally a bad solution to things.
Load
this. It should say "ERROR no NAME query".
If it does, start your server.
Open console (press ~) and type (or paste) in
localClientConnection.authCheck();See if you get an auth fail.
If you do, open console again and type in "tree();" and hit enter.
Find "TCPGroup - Sim Group" and click the + next to it.
Click on "servAuthTCPObj"
In the left box, click "Expand All".
Select everything in the "cmd" box and paste it here.