Petrol-engined chainsaws usually have an engine-driven oil pump, which is prone to getting clogged with sawdust and giving trouble. A few, though, use crankcase pulsations or an air pump to pressurise the oil tank. I'm guessing that your electric saw will have a motor driven oil pump. The most common problem seems to be the oil discharge passage from the pump to the chain, becoming clogged with sawdust. I suggest you clean that - the manual tells you how. If the oil pickup tube, especially the intake filter, is OK and the discharge passage is clear, you'll need to look at the pump drive and the pump itself.
