Here are some potential steps to troubleshoot a stylus not being recognized on a touchscreen device:

1. Check system-level settings and ensure the device and the stylus are properly configured.
2. Install the latest version of OneNote and the latest Windows updates.
3. Install the latest hardware updates for the device and the stylus.
4. Test the stylus on another device, or try a different stylus on the device.
5. Restart the device and the stylus.
6. Contact the device and stylus manufacturer for more help.