I usually take the tube off, and run water through it to clear out anything that might be blocking it. It can be tricky (I usually do it in the bathroom) and then hang it outside to dry.
^
this
bath is ideal. otherwise run it from the taps into the bog

a blockage will normally be an object that was a bit big with some fluff around it.
) and you could hear the increase in suction. checked the brush bit, and there was a huge hair an dust ball stuck behind the roller bit, so everytime i switched the hoover on, it sucked this hairball over the hole, blocking the suction


