External GPS module and Pixhawk GPS signals are not at sync

The GPS module and the Pixhawk 2.4.8 are not at sync. When GPS is blue, the Pixhawk main LED is green and when Pixhawk main LED is blue the GPS blue signal becomes off. Mission Planner software version used is 1.3.77. What could be the reason for the same? The compass calibration is absolutely fine.