You do not have a link list with a handle set to probes-sensors-11-14-super-duty-6-7, or you do and it's empty. Go ahead and create a link list called Probes & Sensors 11-14 Super Duty 6.7 on your Navigation page and populate that link list with links that point to collections, to see collections listed here. Make sure the link list also has a handle set to probes-sensors-11-14-super-duty-6-7.