You either have something caught in the drain pump or a bad pump,that\'s what f21 error code means.remove the bottom panel of the washer and you should unplug it first,you\'ll see the drain pump and the center of the pump unscrews,put down some towels first and then you need a shop vac,turn the middle piece counter clockwise slowly,until the water starts to leak out and vac it up as it comes out,also if water is still in the washer open the door and vac all of it out first,you can also get the drain hose and vac the water out of the washer that way and then remove the middle part of the pump but there will still be water there so be ready with the vac,when the water stops remove the middle piece and see what\'s in there,you\'ll see a rubber hose connected to the pump,with the vac inside the middle of the pump shake that hose,sometimes stuff gets stuck in there to so check that out,if you have to remove it from the pump to clean it out,sometimes the under wire of a bra gets down there so be careful checking the rubber hose you don\'t want anything to stick it and make a hole,then put the middle piece back in,add some water and put it on spin drain to pump out the water to see if it drains,if it doesn\'t you need a new pump,also on some models when the water is in the washer,you hit cancel and the washer will drain.hope this helps and good luck.

This code f21 is a long drain error msg. Try this link