Cannot find any tech info on this unit which unfortunately is normal with LG.
Hopefully someone else with this info will jump in.

If you cannot start it for a several minutes after it shuts down, it could be that the motor is overheating and it's internal thermal protect is tripping.
But since I do not have the tech data I cannot be 100% sure of this.

Try turning the drum in the correct direction by hand, should turn fairly easily.

Check your vent system, they may have a different set up than most for a dryer over heat situation. I did find info on a different LG unit and they had a over-temp thermostat on the blower which would shut the motor off.
Undo the dryer from the exhaust
Run a load
If the load dries correctly then you have a vent problem.
Clean/check the vent system. Make sure the outside louvers open fully.

If you do not want lint in the house.
Take a pair of pantyhose, put one leg into the other and attach this to the dryer exhaust.
Leave enough room behind the dryer so it can blow out like a windsock.
Run a load.

Both the above will allow you to check the air flow and temp.
Also the above is NOT recommended for a gas dryer due to possible carbon monoxide problems.

If the drum turns OK and the unit still shuts off when disconnected from the vent, I would get the unit repaired under warranty.