1. Open the Control Panel so that you can access the Windows Firewall (or else the Security Center, then the Windows Firewall). Click "Start", "Settings" and/or "Control Panel", then "Security Center" and/or "Windows Firewall".
2. If the firewall is enabled, make sure it has been set to allow exceptions, and then switch to the "Exceptions" list.
3. If OKwin is shown in the list of programs, make sure it has a check mark to allow that program to access the internet. If OKwin is not shown in the list, click the "Add Program" button to add it by browsing through the list of program files.
4. Use the "OK" button to close this window and save your changes.
5. Test serving a table in OKwin.