Yes. You can use the Miura reader with all supported mobile devices, as long as the app is installed. However, a reader can only be used by the user that it has been attached to in the gateway manager.
Make sure that you are logged in with this user account and that you have connected the reader via Bluetooth.
It is not possible to use one reader together with several smartphones at the same time.
In any case, be careful with your login data and don’t share it with other people. Don’t forget to log out if you used your login on another phone.