assuming the incoming water spray holes are free of mould/gunge does the soap drawer have a divider that you have to change over if you use liquid or soap powder on a main wash program, this can easily be inserted this the wrong way round after a clean .Note pre wash programs also use a different soap drawer hence you may have put the powder in this one not knowing this.
maybe a good idea to remove the hose to the drum and clean out the caked powder
could always use a plastic wash ball filled with powder in the drum
wirecutterman
July 2009