The FL error indicates a flood error. When the FL error is displayed the drain pump should also be running. You didn't mention if the drain pump is running or humming while the FL error is displayed.
The most likely cause of the washer not draining is a bad drain pump.
First you can try to drain the water out by running the drain pump. The 2nd image gives the instructions for putting the washer into a drain/spin test. The pump should run in this test. If nothing runs then the most likely problem is a bad pump.
The water in the tub can be drained by lowering the drain hose to the ground over a small catch pan.
The 1st image below shows the path of the water in drain. If the drain hose is lowered then gravity should allow the water to drain out. If you lower the hose and no water comes out then there is a blockage in the hose or the pump.
If no water drained out when the drain hose was lowered then I recommend first removing the hoses connected to the pump and check for obstructions.
To access the pump you will need to lay the washer on its back and remove the bottom access panel. See the 3rd image to access and change the drain pump.
Of course the flood switch could be bad or suds in the machine can cause a false FL code but check the pump and the hoses first.
I hope this information is helpful resolving your problem but if you have any additional questions then submit another question with additional details for further assistance.