The issue with the file not being sent could be due to various reasons. Some troubleshooting steps you can try are:
- Make sure the file format is supported by the iPad.
- Check if there is enough storage space on the iPad.
- Restart both the iPad and the computer.
- Update the 3uTools software to the latest version.
- Try importing the files again after reconnecting the iPad to the computer.
If the issue persists, it would be recommended to seek further assistance from the 3uTools support team or consult relevant forums for potential solutions.