Fuzzy Logic MPPT controller MATLAB Simulink

Good day, I am currently working on a boost converter whereby the switch's duty cycle is controlled by a fuzzy logic MPPT controller. The inputs of the controller are Delta Ppv and Delta Vpv, a subsystem with both inputs are connected to the fuzzy controller in MATLAB simulink, where else the output is directly connected to the switch. The simulation result came out with question marks appearing in both input and output ports of the controller. What am I missing in the simulation?