If you are not able to rearrange pages within a OneNote section on Mac, here are some suggestions on what you can do:

1. Restart the OneNote app:
   Quit the OneNote app and relaunch it to see if the rearrange feature works again.
2. Check screen resolution:
   Make sure you update the resolution of the display to see if it helps with the rearrange feature.
3. Check for an update:
   Check for any OneNote updates available and install them to see if there are any fixes for the rearrange feature.
4. Create a backup:
   Create a backup of the notebook file(s) in case you need to restore them at a later date.