UE indicates that the LG front-load washer cannot balance the load for spinning. A very absorbent item or a small load can trigger the alert without there being a motor fault.
The explanation applies to the front-load family documented by LG. On top-load models, the wording and the way to resume may change; check that manual.
Redistribute the load once the door is released
Pause and wait for the drum to stop and for the lock to allow opening. Untangle any clothes bunched together. A sheet wrapped around the rest of the laundry or a single soaked towel concentrates weight in one area; redistributing the clothes can change that condition.
Adjust the amount to the program’s capacity, not just the machine’s maximum kilograms. Do not add items indiscriminately to a full drum or insist on using articles the manufacturer does not allow. See how to distribute the load to prepare a compatible spin cycle.
If it happens with different loads
Check whether the machine rocks on its supports when it is stopped. The vibration during spinning needs the installation and support checked before attributing it to the suspension. Do not increase the spin speed to get past UE. If it appears with varied loads, properly distributed and with stable support, request a service check.
Note which garments trigger UE and whether it also happens with a normal load: this helps distinguish a one-time load issue from a recurring machine issue.