You can perform this check at any time, should you have missed the Windows Firewall Security Alert screen (see below) after first installing the control server Foobar2000 plugin the very first time, or are troubleshooting a connection issue and want to re-confirm your settings.
Because Foobar2000 Copilot communicates with Foobar2000 thru a network connection, it will fail to connect if your PC firewall software blocks access to Foobar2000.
Windows Firewall will by default block network access to any installed program unless you grant access.
The following section describes what you have to check and/or do if you are using the default firewall capabilities built into Windows. If you aren't using Windows Firewall, but instead installed some other vendor's Firewall software, you will have to do something similar, but the particulars will depend on your firewall software.
STEP 1: On your Windows PC, bring up the start menu, under programs bring up 'search' (or Cortana if on Windows 10). Type "allow app" into the text entry field, when you see "Allow an App through Windows Firewall" click on that.
STEP 2: Find foobar2000 in the list. If it is in the list, confirm that both the 'private' and 'public' networks boxes are checked. Also make sure the checkbox in front of the foobar2000 entry is checked as shown in the above figure.
If all these checkboxes aren't checked, click on the 'Change settings' button and then make and save the changes. This will insure your setup will work on any network you may be connected to.
If foobar2000 isn't in the list at all, add it to the list using the 'Allow another app...' button. Then click on the 'Browse...' button in the popup dialog to select the file path to the foobar2000.exe.
In the file dialog, navigate to C:\Program Files (x86)\foobar2000\foobar2000.exe and select it as shown in the figure below.
Then make sure both the 'Private' and 'Public' networks boxes are checked for it in the Allowed Apps dialog.
If you want to restrict access only to private networks versus both public and private networks you can still do so.
Just be aware that depending on your Windows setup, your home network may have gotten classified as 'public' versus 'private'.
If you are having trouble connecting, especially if you have switched networks, check the firewall settings for foobar2000 and check whether the network you are on is classified as either private or public.
You can check how your network got classified by looking under Windows Network and Sharing Center. There you will see your network labeled as either private or public.