Usually that problem is caused by not setting up your realmlist table properly.
In heidisql connect to your server, Then click on emucoach-auth. Open it up and you will see a table called realmlist.
Click realmlist, And then on the right view the data.
Set the data according to how you are setup. I use a separate computer as the server so my data is like this.
Servername, servername.ddns.net, 192.168.254.45, and the rest should be left to default values.
Server name doesn't matter. and if your playing on the same machine that your running the server on, Then all the other addresses can be 127.0.0.1.
If windows firewall pops up, and wants you to click something, Leave it on the default settings and say yes.