A washer door that will not open may be doing exactly what it is designed to do: the lock can stay engaged during the cycle and briefly afterward, especially if water remains in the drum. If the cycle has finished, common causes include undrained water, a power issue, lock failure, or a damaged handle. Do not force the door.
Wait for the cycle and lock delay to finish
Use pause or end as the manual directs and wait the specified interval. Some machines keep the latch engaged until the drum stops and temperature or water level is safe. Pulling on the handle during that period can break it.
Check whether water remains in the drum
If water remains, drainage may be the main problem rather than the lock. Try a drain or spin cycle if the machine responds. If it will not drain, inspect only the user-accessible pump filter as the manual allows and prepare containers because a large amount of water may escape.
A power interruption can leave the latch in an intermediate state
Restore power from a safe outlet or breaker and allow the electronics to restart. Some models have a documented emergency release behind a service flap; use it only as the manual instructs and only after water has been drained.
A loose handle or repeated lock failure needs repair
If the handle moves without operating anything, the door error returns, or the latch buzzes without releasing, stop forcing it. Disconnect the washer before any user-serviceable repair and arrange service if panels or internal wiring are involved.