Error : 'openssl' is not recognized as an internal or external command, operable program or batch file.- while compiling simulink model.

I got below error while compiling simulink model which internally calls cpp file.

Making simulation target "detectFatigue_simulink_sfun", ... 

'openssl' is not recognized as an internal or external command, 
operable program or batch file.
Component: Make | Category: Make error
Unable to create mex function 'detectFatigue_simulink_sfun.mexw64' required for simulation.
Component: Simulink | Category: Model error

code snippet:

function y = fcn(R,G,B)
%#codegen    
%     img = cat(3,R,G,B);
    img = cat(3,R,G,B);
    y=0;
    y = coder.ceval('detectFatigue',img);

Can someone help plz.