This problem has three common causes that you should check.
1. The IR sensor may be placed incorrectly.
The sensor must be touching your TV's bottom frame with the arrows pointing in and lights facing upward to give a useful reading. You can read more about the sensor here.
2. The WAVE may not be calibrated with the new reading.
If you have just adjusted the light to green, you must calibrate to enable touch.
3. The WAVE's light wall may be reflecting off of your TV screen.
When the angle of the lights on the Android Box becomes too acute, the infrared light wall will reflect from your TV screen (see left image below). This can give a green light reading but makes it impossible to calibrate. To calibrate, the WAVE's light wall must be parallel to the screen (see right image below). Please refer to the quick fix guide to re-mount your WAVE and realign the wall. You can read more about fixing reflections here.
4. Your TV may have an unusually thick or thin bezel.
If your TV has a frame half an inch or more from the screen and you're having difficulty calibrating, try moving the sensor to a mix of yellow and green to calibrate. If the bezel is hair thin (1-2mm) you should try to get a mixed red and green reading before calibrating. This can help eliminate dead zones at the top, bottom, or corners of your screen.