1. Go to touchscreen > Maintain, make sure power is set to "x1.0".
2. Check if the focus is adjusted at the right height.
3. Check if the lens or mirrors are dirty or damaged. See "Wiping the Lens"
4. Check if the optical path is aligned. See "Optical Path Alignment"
If the steps above didn’t work, please provide us the picture of the tape with dot shot in step 4 for further assistance. (3 tapes in total for three reflection mirrors and they'll need to be all on the reflection mirrors while you take the pictures. See the video tutorial.)
Thank you for your cooperation.