If you repeatedly get "scan failed" it may be caused by a number of things.
Once you get it right once it is pretty easy but pay attention to the following:
- Do not scan too slow.
- When the C-Pen touch the paper and the light goes on - start scanning. Do not wait too long.
- Keep an even speed.
- Avoid rotating the C-Pen while scanning.
- Make sure that the text line to be scanned is centered between in the opening gap of the C-Pen.
- Keep the C-Pen at about a 90 degree angle towards the paper when scanning.
For more information check out this - How to scan