Hi Moon,
the Tobii eye trackers are designed for desktop use, and they won’t work at distances of two meters: it’s a limitation of the technology. It might still be possible to get tracking at that distance, though, if you mount the tracker in the working range of the tracker instead of on the screen. But since that is a non-standard mounting it will take some work to get it all set up properly, and you’ll have to use the Gaze SDK rather than EyeX.
The other question, about the calibration, is more puzzling.
-Are you using the EyeX controller or the REX?
-Are your eyes about 60-80 cm from the tracker?
-If you are using the EyeX controller, are the lights on steadily when you try to calibrate?