Oil is pushed into the canister from the galley, pressurizing the canister. This forces the oil through the filter and out the hollow lid bolt to drain over the timing gears.
You should be able to remove the lower hose, and with the engine running, get oil out from the bottom hose (once the canister is full). If you don't, you need to inspect the inlet line for blockage, the bolt to insure it is clear, and the outlet hoes to make sure it hasn't collapsed or gone bad.
Remember, this is a bypass system, it only cleans a small amount of oil at any time, unlike modern systems that force all oil through the filter before it reaches the galleys.