Cant get simulink FFT Spectrum Scope to display signal from sine wave imported values

Hi, i have a sine wave, with the values being imported from a csv file. Ive loaded this into the signal builder block in simulink. When i connect it to the Scope i get my signal displayed fine.

I tried to connect the signal builder to the Spectrum Scope but matlab gave an error saying to the effect of saying only discrete values are allowed for this input. So i connected a Zero-Order Hold between the signal builder and the spectrum scope to get rid of that error

However when i run the model the Spectrum Scope doesnt display anything at all - any ideas what Im doing wrong? thank you.