: Turn your Mac's Bluetooth off and back on via the Control Centre or System Settings. Surface Cleaning
When the Magic Mouse battery gets low (below 10–15%), it often disables scrolling to save power. Go to System Settings → Bluetooth → click the i next to your Magic Mouse → check the battery percentage. If it’s below 20%, charge it for 10–15 minutes and test scrolling again. magic mouse not scrolling
Magic Mouse scrolling often fails on Windows because the default Bluetooth connection lacks the specific Apple "touch" drivers. How to Scroll with Magic Mouse 2 (tutorial) : Turn your Mac's Bluetooth off and back