2006 Other Holden Models no power?

Transmission problem
2006 Other Holden Models 4 cyl Front Wheel Drive Automatic

Hi there

I was driving home from work lsat night when my Holden Viva changed itself into 1st gear, the engine light came on, and I lost all power through the acceleratorn and it wouldnt change out of 1st gear. I had to pull up at a red light and couldnt accelerate over 20km's when the light went green. 2 hours later my husband took it for a drive and it changed gears without issue.
This morning I went to drive it to work and couldnt get it out of park into reverse. My father in law tried at the time and couldnt get it to shift either. A few hours later he tried again and it went straight into gear with no hassel.
Is it the transmission? Or the neutral safety switch? Or something else?