Check the connections at the battery, and the connection of the ground strap at the engine case down by the oil inspection window by your right foot.  Check the electrical connectors under the tank....they can work loose if the last person that put them together didn't get them far enough together for the latch to lock in place.

I'm guessing by now you have a volt/ohm meter ,if not you need one! If your battery is dead ,and your bike quit underway you might want to check your alternator ,even if the bike 's not running you can pull the plug from the rectifier (three yellow  wires ) and test for ohms between the leads (three tests ) there should be slight resistance , I think about 1or2 ohms)if you find the ohms needle  doesn't drop at all you have a bad winding ,and the alternator is not charging the battery,and your bike can't even run off the alternator .Once your battery drops below 10 volts your spark dies ,and there 's no juice to restart.If you can recharge the battery and run the bike you can test for AC voltage across the same 3 wires ,It should be about 100 AC volts at 5000 rpm.

The battery is fully charged, suppose I'll check the alternator and then I'll look for the battery ground.

If the bike is running and suddenly stops - it likely has nothing to do with the alternator.  If the battery is not being charged as you ride....the lights will slowly grow dim, and the bike will begin to misfire before it suddenly stops.  Same for the battery.....if the bike is already running and the battery fails.....the alternator will keep the bike running until you shut if off - then it won't restart if the battery is dead.

You should listen to us old guys....check the connections to the battery and the ground at the engine....and check the wiring connectors under the tank before you do anything else.  (Provided you have proven your fuses are good).