Suction power is too weak.
The dust bin is full of dust.
Empty the dust bin.
Filters are clogged.
Clean the pre-filter and the exhaust filter. If the suction power is still weak after cleaning the filters, replace the filters.
Inlet is clogged.
Remove any foreign objects from inside the product body or the extension pipe.
Foreign objects are stuck to the rotating brush, or in inlet port.
Remove any foreign objects (thread, hair, etc.) from the rotating brush or the inlet port.
Warm air comes out of the product body.
Warm air is vented while cooling the motor inside the product body.
This is normal.