gps status in the mavlink console output?
If you see that it's not even recognizing the module, you probably have a UART problem.
Drotek's documentation is not very clear on this, but you need to make sure that the module is configured in rover mode. This only affects how the UART pins are connected.
Depending on when you bought the module, I believe you might either have a switch on the board or a solder bridge. The solder bridge needs to be connected for the rover port to work.
Alternatively, you can also just use the TELEM port, where you will have to switch the RX/TX pins.