There can be several reasons why a Ultenic U11/U11 Pro cordless vacuum suddenly no longer sucks properly. 

Below can be some main reason:

1) The dust container is too full.

2) The filters are clogged, dirty or need to be replaced.

3) There is a low battery life.

4) A motorized squeegee gets stuck on the floor.

If the problem persists, please contact our Customer Service team.