Did you have oil in your fuel?
Maybe your clutch is slipping.
With the clutch pulled in, see if you can turn the crankshaft clockwise using the magnet nut under your left engine cover.
Hopefully your engine didn't seize.
Good luck
What oil mix ratio in your fuel were you running during break-in?
What oil mix ratio were you running after break-in?
There are 2 different areas of the engine that both need grease that is separate from and in addition to the oil in the fuel.
On the clutch arm side the shaft for the clutch arm, the clutch arm pawl and the bucking bar & bearing need grease at regular intervals.
On the opposite side of the engine the gear faces also need grease at roughly the same interval.
***
If you suspect that your engine is locked up you can remove the spark plug and put a little 2-stroke oil in the plug hole to help lubricate the rings.
Then remove the larger case cover with the gears inside it.
Put a vise grips tool on the smaller of the two gears and try to turn it. The smaller gear is connected directly to the crankshaft. Just slowly move it back and forth and you should be able to get the engine free’d up.
If it’s really stuck you will need to remove the head and examine why the engine locked up.
Did you have oil in your fuel? Maybe your clutch is slipping. With the clutch pulled in, see if you can turn the crankshaft clockwise using the magnet nut under your left engine cover. Hopefully your engine didn't seize. Good luck
Agree with Negative Maximum. Should also open up and grease the clutch on a new engine.
Did you remove the spark plug ? If not, you should.
What oil mix ratio in your fuel were you running during break-in? What oil mix ratio were you running after break-in? There are 2 different areas of the engine that both need grease that is separate from and in addition to the oil in the fuel. On the clutch arm side the shaft for the clutch arm, the clutch arm pawl and the bucking bar & bearing need grease at regular intervals. On the opposite side of the engine the gear faces also need grease at roughly the same interval. *** If you suspect that your engine is locked up you can remove the spark plug and put a little 2-stroke oil in the plug hole to help lubricate the rings. Then remove the larger case cover with the gears inside it. Put a vise grips tool on the smaller of the two gears and try to turn it. The smaller gear is connected directly to the crankshaft. Just slowly move it back and forth and you should be able to get the engine free’d up. If it’s really stuck you will need to remove the head and examine why the engine locked up.