How to solve this problem?

Hi @kaeyakai !

This may be because:

• Your account’s music is already playing on another device that belongs to you
• Your account’s music is already playing on another device that someone else is using

Note: Deezer Family users should check that all family members are using the correct profile to listen to music. If two people are listening to music on the same profile, it will result in an error message informing you that your account is being listened to on another device

All text see in link below 

https://support.deezer.com/hc/en-gb/articles/360001430465-Account-Being-Used-On-Another-Device

@kaeyakai 

Maybe you have left your Deezer account logged in on somebody else's device !?