Pump Motor Hums Shuts Off Moments Later

https://drive.google.com/file/d/1ARmfACtdiKxmpLBQmCn_imGyrCNXH2id/view?usp=sharing

Unsure what happened. I shutdown the equipment and backwashed. When I went back to turn on the power there was nothing, only a humming sound. What could be the problem?

There is a link to a video of the sound above.