Defective water pump.

the pump is underpowered, this reduces the back pressure inside the pod when brewing, allowing the full 8 ounces to flow through

The pump stopped working

Disappointed pump stopped working less than 8 months after purchase!

The pump refuses to suck up the water from the reservoir and it produces less and less coffee.

It starts making weird pumping noises like it's

Disappointed pump stopped working less than 8 months after purchase!

The pump is too weak

Like other reviewers have noted, the pump inside is failing

But clearly there is a big issue with the quality of these machines if other people are consistently reporting this problem, as well as the water pumps dying so prematurely.

This one lasted 4 months before the pump broke