This is an error you would get if there are more devices linked against your subscription than is permissible.
To remove the unwanted devices, log in to your account from any browser using URL www.hoichoi.tv
Once logged in you would be guided to the settings where under the "device management" section, you would be able to remove the devices using the bin icon.
NOTE: If you are using the Mbrowser, after clicking on the bin icon, you would need to slide the screen towards the left to remove the devices.