Magic Mouse 2

Hi MM2Difs,

Thank you for using the Apple Support Communities! We would like to clarify your issue. Are you unable to connect your Magic Mouse? If so, the guidance listed below may help:

If you can't connect your Magic Keyboard, Magic Mouse, or Magic Trackpad to your Mac

Turn the device off and on

Magic Mouse has a switch on the bottom of the device, and Magic Keyboard and Magic Trackpad have a switch on the back edge of the device. Slide the switch to turn off the device (no green is visible), then slide the switch back to turn on the device (green becomes visible).

Make sure Bluetooth is turned on

Using your Mac laptop's built-in trackpad or a USB mouse, choose Apple menu  > System Settings (or System Preferences), then click Bluetooth. Make sure that Bluetooth is turned on. 

If you don't have a USB mouse and your keyboard is connected, press Command-Space bar, enter Bluetooth File Exchange in the Spotlight search field, press the Return or Enter key, then press the Return or Enter key to turn Bluetooth on.

If you still can't turn Bluetooth on, restart your computer, then try to turn Bluetooth on again.

Connect the Lightning cable

Connect your wireless accessory to your Mac with the Lightning to USB Cable or USB-C to Lightning Cable, wait 1 minute, then disconnect the cable. This pairs the accessory with your Mac and charges the built-in battery. To check your accessory's charge level, click the Control Center icon  in the menu bar, then click Bluetooth.

Check for wireless interference

If your accessory won't stay connected wirelessly, there might be interference with other wireless devices. Learn how to resolve Wi-Fi and Bluetooth issues caused by wireless interference.

Hope this helps!

Have a great day.