DIAGNOSIS Rapid suction loss almost always points to something filling up the primary collection path way faster than it should. On this model, the most likely spot is the pre-motor filter screen, a little mesh guard right under the dust cup.
FIX First, empty the dust cup. Then, look at the bottom of the vacuum where the cup sits. You'll see a rectangular mesh filter. Pop it out. This thing clogs instantly with fine dust. Tap it clean or rinse it under water and let it dry fully before putting it back. While you're at it, check the hose connection at the back of the vacuum body—sometimes a plastic bag or large object gets sucked up and lodged right there.
IF THAT DIDN'T WORK The next checkpoint is the hose itself. Unplug both ends (from the vacuum body and from the wand). Shine a flashlight through it and look for an obstruction. You can use a long, flexible item like a broom handle to gently push a blockage through.
HEADS UP Never use the vacuum without that pre-motor filter screen in place. It's there to protect the motor from larger debris, and running without it is asking for a burn-out.