Dishwasher not fully emptying/not washing items properly

Hi all I’m completely new to this site and forum so forgive me if I’m doing anything wrong!
I’m in desperate need of help! I’m on my third dishwasher-first two 2nd hand this one brand new but given to us not bought from the high street.
I’m thinking my drainage pipe is at the wrong angle, my lazy husband can’t be bothered/isn’t interested in helping me solve this issue but as a busy working mum of three I’m absolutely desperate to have a functioning dishwasher!!! I’ve taken a photo to show you all of the pipe on question. But basically the dishwasher doesn’t empty fully & the plates come out dirty. I’ve checked the filter it’s clear…so, given that we’ve had the same problem with all three machines it’s prob not a mechanical fault but a plumbing issue. Not sure whether to calm out a plumber of a dishwasher engineer. Newly qualified plumber friend was totally clueless-HELP!!!!!!!
Kirsty xxx