If you are listening to music on your mobile device and the following message appears: "Your Deezer account is currently in listening mode on another device. Your Deezer account is strictly personal and may not be used to play music on another device at the same time" then it is for the following reason. As this message states, your account is strictly for your own personal use. You cannot simultaneously be connected to 2 devices and use them both at the same time. By clicking "Ok" you can continue listening. If the message re-appears then verify that nobody else is using your account.