Ok, assuming that the plumbing is correct ... am i right in thinking you are using a liquid or liqui-tabs ? ... they dont contain any bleach and are a major contributor to smelly machines along with the fact that people are washing at 30 / 40 degrees only these days ... the partially disollved detergent remains behnind, provides agood breeding ground for the bacteria in the machine (from dirty clothes) and they then breed ... hence the smell. To resolve: 1 select the highest temperature possible for the machine 2 place 2x tabs of a bio detergent in the drum with 3-4 items of material you dont really care about (t towles / old t shirts etc) to create agitation of the water and let it run full cycle ... the extra heat & the bleach will break up the gloop to the rear of the machine 7 the bleach will kill off the bacteria in the machine ... repeat 1-2 a month depending on the frequency you use the machine ... but really you should be using a bio detergent as well as non bio / colur / liquid to get the best results.