Won't complete cycle get an F 21 error

Could be several reasons:
- Selected the "Night cycle" program (means standing with the drum full of water, reason: too much noise in the spin cycle)
- Set to the "Rinse hold" (means standing with the drum full of water, reason: wrinkles on the clothes)

According to your description I think that this is not a failure otherwise error E20 will be appears on display.

Once the washing programme has come to an end, END illuminates on the programme progress display.
If RINSE HOLD was selected, the display beside the START/ PAUSE button flashes.
1. After a rinse hold, the water must first be pumped out:
- Either press the START/PAUSE button (the water is pumped out and the washing is spun according to the completed programme;
After the START/PAUSE button is pressed again, the spin speed can still also be changed during spinning), or
- Turn the programme selector to PUMP OUT and press the START/PAUSE button (the water is pumped out without spinning),or
- Turn the programme selector to SPIN or SHORT SPIN and press theSTART/PAUSE button (the water is pumped out and the washing is spun or gently spun).
At the end of this programme step, the END indicator will illuminate.
2. Open the door.
As soon as the DOOR indicator lights up green, the door can be opened.

Dado

Drain pump may be clogged or need to be replaced may run but not pump blade stripped in pump

Always supply a model number, each model has it's own foibles. It is very hard to assist without full details.
BUT, is this an "LAT" series Maytag washer??
If so, this is a normal rinse, the manufacturer calls it a "Spray Rinse" and it is quite normal.it only adds the water during the spin cycle, after the rinse water is ejected and then only for about 1 minute, the water passing through the fabric as it passes by the water inlet flume and empties during the spin.

Unplug the washer. Then plug it back in and press the button that turns it off. This should unlock the door. Same thing happened on mine and there was a kink in the drain hose. Once I unkinked the hose, unplugged it, plugged it back in, turned it off, then I was able to run a drain & spin cycle to get the water out of the load that was in the washer. I then ran a full wash cycle (they'd gotten stuck in the first drain & spin cycle of a wash) and everything seems to be fine now.

I have the manual for this machine. Under "Code 21" it says the following:
"F21" (Drain Problem) Select STOP twice to cancel the cycle. Unplug washer or disconnect power. Check the following: Is the drain hose kinked? Is the drain hose frozen? Is the drain hose clogged? Is the drain hose more than 96" (2.4 m) above the floor? Plug in washer or reconnect power. Re-select cycle and press START. If the problem remains, call for service.
For "SUDS" code, the following:
"SUD" (Suds Routine) When excessive suds are detected, a suds routine automatically starts. This routine removes extra suds and assures proper rinsing of your garments. "SUD" is displayed during rinsing to inform you that Suds Routine was activated. Use only HE (High Efficiency) detergents.
Here is some more information that may help you as well:
"F" Codes other than F20, F21 and F22 Select STOP twice to cancel the cycle. Select DRAIN & SPIN if there is excessive water in the washer. Re-select cycle and press START. If the problem remains, call for service.
I hope this is of some help to you, Please rate and comment, Thank You
Joe

The F33 error code indicates a pump drive system error. If the pump ohms out correctly & the harness is secure I recommend replacing the CCU (central control unit).
Please see the following image provided for instructions.

CLICK HERE

Remember to disconnect power to the washer before attempting access.

Thanks for using FixYa&^%%$

This means the water is not draining out like it should. I solved this problem initially on my washer (my drain pipe was clogged), but now (about 4 months later), I have a flashing F21 and 5d, because of a clog some- where. I can drain and rinse (after this cycle, the door will unlock), and the tub spins, but I can't complete a cycle. Lots of debris has come out with rinse water, but I still seem to have a clog somewhere. I can complete a wash load by manually switching the settings.

I'm guessing the HOSE is the drain hose.
The goop is causing the drain motor to overheat causing it to report error. (luckily or it'd burn out).
Give it a empty load with nothing in it to see if it flushes it all out.
Just water.
See if it completes full cycle and check pump filter again to see if clean.
TIP. Make sure you check ALL pockets before you wash clothes.
;)

will sence it will spin once the water is out .that must mean your pump is restricted.unplug go to buttom of washer find pump and clean out

REPL/ YOUR PUMP F 21 LONG DRAIN .. MAYBE JUST NEEDS TO CLEANED OUT