Go to System Settings > Bluetooth , turn Bluetooth off for 10 seconds, and then turn it back on.
Click (or Accessibility > Pointer Control > Mouse Options) and verify that Use mouse for scrolling is enabled. On Windows magic mouse not scrolling
If the scrolling feels "backwards" (scrolling up moves the page down), this is actually the default "Natural" setting. If you prefer the old-school way, simply uncheck this box. Go to System Settings > Bluetooth , turn
This isolates whether the issue is system-wide or account-specific. Go to System Settings > Bluetooth