Magic Mouse 2 not responding at login screen

Hi everyone,

I bought a brand new iMac a week ago and after 2 days of use the mouse does not respond at the login screen. I have to login using the keyboard, which work just fine. Once I logged in with my keyboard the mouse work normally, even when it goes to sleep mode the mouse work just fine at the login screen. The problem keep happening when I am coming back once the iMac have all the users logged out or after a shutdown. I called tech support and they instructed me to disconnect the mouse (via bluetooth) and reconnect it again but it did not fix the problem. And, by the way I am running the last version of El Capitan. I will appreciate any advice in this matter, thanks.