Use NFourierTransform to do a two dimensional fourier transformation and plot a picutre(mathematica)

Question

When I use the mathematica to calculate a numerical fourier transformation of two dimensional, there is no answer and even error reminding, just skip and finish without no result. Could you tell me what is wrong with it?

Clear["Global`*"]
Needs["FourierSeries`"]
f[t_, x_] := 
 UnitStep[1 - t] UnitStep[t + 1] UnitStep[1 - x] UnitStep[x + 1]
Plot3D[f[t, x], {t, -2, 2}, {x, -2, 2}, PlotRange -> All]
Plot3D[NFourierTransform[
  f[t, x], {t, x}, {omega, omega2}], {omega, -20, 20}, {omega2, -20, 
  20}, PlotRange -> All]