Play/pause buttons launches iTunes instead of playing/pausing the Deezer app I am using the Deezer app music. It worked well, I could use the media buttons to control play/pause/next track/previous track. But a few days ago, (after an macOS update?) now when I hit play/pause it launches iTunes instead of controlling the Deezer app that is already running and playing music. It was correctly functioning before, so I don't know where this change of behaviour is coming from. This is very annoying as it makes the Deezer almost unusable as I have to bring it to front to control it.
Found the answer on the Deezer community forum:

You have to allow Deezer the accessibility rights, go to:


System Preferences
Security and Privacy
Privacy tab
Choose "Accessibility"
Add "Deezer" to the allowed software


You'll have to unlock the configuration by clicking on the lock and enter your system password.

The original answer can be found here.