CASE #1: You (or someone else) are using more than $this.View.AuthResponse.DeviceLimit devices and/or browsers at the same time → Sign out of devices and/or browsers you are not using
CASE #2: You are surfing in private mode → Always log out before closing the browser window
CASE #3: You refuse connection cookies in your browser settings (or an update has changed your settings) → Change your browser's cookie acceptance settings
IN ALL CASES → Clicking on "Continue on this device" solves the problem
What happens when I click "Continue on this device"? You can use your account on this device and all your other devices will be deregistered. You can still connect to it up to the limit of $this.View.AuthResponse.DeviceLimit devices.
How can I see connected devices Go to your Members Area and click "Manage Devices". If you go there after clicking "Continue on this device" there should only be one.