In order to install Deezer with Software Manager,
Then log out and log in back to let your desktop environment (Cinnamon, Mate, XFCE) find out that a new application has been installed. Otherwise, you may see mismatched application icons and other funny bugs.
Alternatively, launch a Linux terminal emulator,
type flatpak install nuvola eu.tiliado.NuvolaAppDeezer
and press the Enter key to install this package.
Then log out and log in back to let your desktop environment (Cinnamon, Mate, XFCE) find out that a new application has been installed. Otherwise, you may see mismatched application icons and other funny bugs.
flatpak run eu.tiliado.NuvolaAppDeezer