video problems on cubase 8.5

Hi everyone, I just purchased this great Steinberg Cubase 8.5 software and I´m really happy it to record, but there´s one minor issue that I can´t figure out. I´d like to know why the videos I recorded on mp4s don´t work on my cubase 8.5.
If its possible, can anyone give me some feedback on this minor situation?? Thank you!!!