Diagnosis
Yeah, this one's common. The child lock is active. It's either been turned on accidentally via the control panel, or the washer still thinks there's water in the drum, preventing the door from unlocking for safety.
How to Fix It
First, try to turn off the child lock. Press and hold the Delay StartStart/Pause
If That Didn't Work
If the padlock symbol is gone but the door remains mechanically locked, there could be residual water. Manually trigger a drain: select the DrainSpin program and press start. Let it run for a few minutes to clear the tub. After it stops, the door should unlock.
Heads Up
Never force the door open. If it's truly stuck after trying these steps, the door lock latch itself (a part called the door lock strike) might be faulty, which is a known wear item on these models.