I agree with the others ........... probably Earth leakage current. It's inherent in W/machines, cookers, freezers etc. It's just the way they're made.
......... but, recently, I had to deal with this for someone. Their problem was with the shower. Nothing wrong with it. (There shouldn't be any Earth leakage with a shower anyway.)
I tested the RCD (trip), and it was tripping at less than the current it should operate at (30 milliamps). I simply replaced the RCD and no more problem.
You don't say......... you may not have an RCD.
It's just a thought. Otherwise, as they say, a new machine needed.