1. Spark Plug coil / coil
2. Fuel pump
3. Starter
4. Weak battery
5. Charging coil
6. Electrical / Electronic fault
7. Cylinder head (low pressure)

... the list goes on.

Best to take to a realiable mechanic or if the bike is new, claim warranty.

If the mechanic do not know where to begin or logically check after you explained the symptom, i think you better high tail out of there and find another one.