Undefined function 'fomcon' for input arguments of type 'char'.

Dear friends hi

I just download FOMCON from: https://www.mathworks.com/matlabcentral/fileexchange/66323-fomcon-toolbox-for-matlab

and add it to matlab as: https://www.youtube.com/watch?v=QY8xhCEoIOU

but I have the error: Undefined function 'fomcon' for input arguments of type 'char'.

what should I do to solve the problem?