The clutch drum or chain sprocket is spinning without engaging the chain. The chain brake is likely engaged. Disengage the chain brake by pulling the hand guard toward the front handle. The chain should rotate when you press the throttle.
If the chain brake is disengaged and the chain still doesn't move, inspect the drive components.
- Check the chain tension. An overly tight chain at operating temperature can damage the crankshaft and bearings.
- Check the chain sprocket for wear. A worn sprocket won't drive the chain properly.
- Check the guide bar groove depth. If it's less than 6.0 mm for a 3/8" chain, the drive links are scraping and the chain won't ride correctly.
If that didn't work, the clutch springs may be worn or the clutch shoes are contaminated with oil. This requires inspection by a specialist dealer.
Heads up: That whining is the engine spinning without a load. Don't hold it at high rpm like that for more than a few seconds. It leads to overheating.