Hi Im John I will help you with the error code f21.
Does the washer completely empty the water from the tub ?
Can you send me the model number please.
Do your clothes come out dry after the spin cycle ?
It takes a really long time and it was a very small load
I can't find it and it is stuck in the cancellation mode.
The problem is with the pump filter its clogged not allowing the waster to drain out as fast as it should, Remove the bottom front panel and clean out the filter, this will help you with the cleaning of the filter.
If you require more assistance let me know please.
Your very welcome .
Thanks and God bless.