why triangulate function in Structure From Motion From Two Views does not not work ?

in matlab 2016a i use the triangulate function in matlab to get 3d 3D spatial coordinates from two photographs by using the example:(Structure From Motion From Two Views) but its not work , the error message is {Error in triangulate (line 10) A =[x1(1,i)*P1(3,:) - P1(1,:);

Error in StructureFromMotionExample (line 153) points3D = triangulate(matchedPoints1, matchedPoints2, camMatrix1, camMatrix2);} please can you helpe me