Clean the device with canned air to blow out the sphere properly. The white tile should be cleaned with a micro fiber cloth or lint free lens cleaning wipe. You may use DI water if necessary but avoid use of solvents as they may causing pitting of the surface. Separate the units black light trap into two pieces by pushing on the tabs and pulling the trap apart. Blow off the conical pyramid found on the bottom piece. Put the calibration block back together and attempt to calibrate.
If this is done and there is still a failure than have the customer close the software they use with the device and follow the link below to our website. Download the Calibration utility zip file and Extract all by right clicking on it and selecting Extract all. A folder will be created on the desktop with the same name. Open the folder and look for the Cixx CalErrorUtility_v4.0.exe. Double click it and the item should return a failure or success message. If it is a failure related to connection please ensure the driver is installed on the PC. If it is a success message try to calibrate the instrument. If it persists to fail calibration the unit will require service.