Symptom: A321/A221 is not transmitting RTK correctors to the rover.
Possible cause: The application firmware not being selected on the base station.
Resolution: Arrow down to "System Setup" and press enter. Press enter for "Display Apps". Then the menu will display "1 In Use" and "2 Other". If the "1 In Use" menu doesn't display SBASRTKB - the B on the end is for BASE. if the "2 Other" displays the BASE firmware instead, you can arrow down to "Swap Application" press enter and the display will read "Resetting" and then the application will be swapped.