Yes, blocked jets.
I use a cable tie thing to clean my jets out - stiff enough to do the job but flexible and no fear of breaking.
Take the drawer out, take it pieces and give it a thorough clean. A bottle brush is good.
Now clean the inside of the drawer, as far back as you can - the bottle brush is good here too.
Do the jets.
Now reassemble the drawer and run the machine on the hottest wash using a cheap biological powder (must be powder). This will clean the bits you can't reach.
All washing machine manufacturers recommend you do this three or four times a year because the low temperature, non-biological washing that we mainly do does not kill any bacteria in the machine.