Num Lock is likely disabled.

Windows: Open the On-Screen Keyboard (Start > Settings > Ease of Access > Keyboard). Click Options, check "Turn on the numeric key pad," click OK, then enable NumLock on the On-Screen Keyboard.

macOS: Go to System Settings > Accessibility > Mouse & Trackpad and uncheck "Enable Mouse Keys."

If that does not fix it, contact support@satechi.com.