I am trying to plot symbolic variable in MATLAB, for which I have used the same strategy that is available in

Rewriting the expression does not change it at all:

rewrite(X*H, 'exp')

Either way, when computing the inverse Fourier transform:

right=ifourier( X*H,t)

Documentation on the ifourier function states that:

If ifourier cannot transform the input, then it returns an unevaluated call to fourier.

Since it cannot evaluate explicitly the function, it cannot plot it.