Be sure to charge the M1 mouse for at least 2-3 hours with the included Type-C to Type-A charging cable until the Blue LED turns off. Keep in mind, that the cable is only used as a charging cable and cannot be used as a wired connection.

Unpair mouse from Bluetooth list. 

There is an (i) icon next to every paired device on your bluetooth list.

Select the icon for the device you want to disconnect. In this case, select the "Satechi M1 Mouse". 

It will ask you again if you'd like to forget this device as you will have to reconnect the mouse after forgetting.  

Once you've forgotten your mouse, Restart your computer. Once booted back up, hold down the pairing button located underneath the mouse for at least 3-4 seconds to place the mouse into pairing mode.

If the issue continues, please also test on a different device to see if you can replicate the issue.

M1 Wireless Mouse Quick Guide