If you don’t recognize a device using your account, you may have left your account logged in on someone else’s device. If you don’t have access to that device, you need to ask the owner of the device to log out of your account.
If you don’t know who it might be, sign out remotely from your account page. For extra safety, you can change your password.
If you think someone may have access to your account, we’d recommend following these steps.
Didn't help? Search for more Spotify Answers, or create a new thread and ask the Community.