Firstly, upgrade the browser to the latest version. After that, navigate to Adobe Downloads page, click the Install now button, save the file to your computer, close the browser and install it following the on-screen instructions. Launch Mozilla Firefox, press Ctrl + Shift + A key combination, click the Plugins menu and enable Adobe Flash Player/Shockwave Flash tools.
If you still have issues, go to Start > Control Panel > System and Security > Windows Firewall > Allow a program through Windows Firewall and check the box next to Muziic Player. If you can't find the application in the Allowed programs and features window, press the Allow another program button, navigate to the installation directory, select the executable file and press Add.
After that, from the Advanced Settings select Inbound Rules > New Rule. Check the Port box, click Next, select All local Ports and follow the self-explained steps. Also, make sure that your security program doesn't block the connection. If the error persists, reinstall the application.