Bought a pressure washer with an attachment like this, the hose kit the website recommended didn't fit, what do I need? (Hose comparison in second pic)

They recommended a hose kit with the machine and none of the plastic bits that came with it fit, and clearly the hose doesn't fit around this brass end piece at all, as they are more or less the same size. What can I use to attach a hose to the washer? Ideally something quick, cheap and convenient (as I've already spent a lot.)