What is a de Error code on an LG Washing Machine?

According to my machine today, it isn’t feeling well, it’s display panel just keeps saying de.

I opened and closed the door a couple of times, I changed the wash cycle options, and it accepted it on the Cotton Quick option.

Once it was working I decided to try to find out the actual cause.

de = Door Error

Copied from the LG Website:

de

When you see the DE error code, it means a “door error”. This is a sign that either the door is not shutting, locking or opening. Most of the time, this is a simple fix and service is probably not needed. Here’s what might be happening and what you can do.

1. It might just be a malfunction. If the code appears mid-cycle or at the end of the cycle, power off the washer and unplug it. Wait for five minutes before plugging it back in. Power it on and see if the door latch releases. If it doesn’t, service will be required.
2. An item may be caught in the door. Unplug the washer and wait five minutes before plugging it back in and turning it on. If the door still doesn’t unlock, the item could be pushing on the door and preventing the latch from unlocking. Service may be required.
3. Is the door or gasket damaged in any way? That may prevent your washer from latching or locking, resulting in a DE error code. Check your warranty policy to determine coverage under the manufacturer’s warranty.

Funny… The error appeared after I closed the door and then selected the Quick 30 wash, I changed to the Cotton Quick option, without opening the door, and it was OK.

Other Error Codes:

ue = unbalanced error
oe = not successfully drained the water
le = a problem with the motor