Was bumped and turned off. It will not turn back on. What can be the problem?

What exactly do you mean by 'Will not start'? Does it do nothing at all? Does it crank very slowly? Does it 'Clunk' then do nothing? Comment below with more information and I'll see if I can help more.
Get the starter motor and its wiring connectors Re-checked you do sometimes get 'Dud' car parts even when new. I had a brand new wheel bearing that lasted 140 miles then collapsed.
Bump starting doesn't use the starter motor at all to turn the engine. Bumping is where you start the vehicle using a 'back to front' method. Bumping in gear turns the wheels, which turns the transmission, which turns the flywheel, turning the crank to start the engine missing the starter motor out altogether.

check steering ball joints for wear. Check for loose wheel bearings. Check front end suspension

i think you need to check that nothing has come lose inside.

To fix this error.... Go to settings, general, location services (must be turned on) and turn the app Bump to "On". Fixed the problem for me

If your at lock either way and backing up, it usual is the CV joints are turning at their maximum and have a little bit of a bind at that angle. Nothing out of the normal unless it feels like it went over a speed bump. If it's just a little slight bump then it's the CV's at their maximum angle.

sounds like a short in the lcd inverter they cost about 40 $ us but to install it will cost about 1 hr labor (60-80 $ at most shops) it might not have to be replaced if it only does it when bumped it just might be a loose connection

When the key is severely worn, the bumps become too short to push the little plungers in sufficiently. Push the key toward the bumps as you turn it. If this works, get a new key made. Possibly you will need to present the key for copying with a little tape on the back to make it wider.

2 POSSIBLE PROBLEMS, STEERING SHAFT WEAR. MORE IMPORTANT SAFETY WISE IS THE LOWER CONTROL ARM BUSHINGS. EASY FOR A MECHAINC TO SEE AND SHOULD CHECK ON A LIFT FOR A MINIMAL CHARGE.

clicking may be ujoints

try this: turn it upside down and run it-then bump it to reverse it...same result?