why i getting this error Cannot plot 1/exp(2*w*i): This function has no real values

 syms w t
 X = exp(j.*-2.*w);
 subplot(2,1,1)
 ezplot(X, [-10 10]);
 Xf = fourier(X,t);
 subplot(2,1,2)
 ezplot(Xf, [-10 10]);

error

Error in ==> ezplot>ezplot1 at 422 error(nargchk(4, 6, nargin, 'struct'));

??? Output argument "hp" (and maybe others) not assigned during call to "D:\Matlab\toolbox\matlab\specgraph\ezplot.m>ezplot1".

Error in ==> ezplot at 146 [hp, cax] = ezplot1(cax, f{1}, vars, labels, args{:});

Error in ==> sym.ezplot at 58 h = ezplot(char(f),varargin{:});

Error in ==> lab09 at 5 ezplot(X, [-10 10]);