E16 on documented Bosch washing machines indicates that the door is not locked properly. Check for trapped laundry, overloading, and the latch before trying to start it again.
Check the door without forcing it
The manufacturer's documentation suggests opening and closing it again and using Start/Reload. Do this only when the program allows opening: if there is water left, the temperature is high, or the drum is moving, wait for the safety procedure.
With the door open, move any clothing edges away from the seal and latch. If the load is pressing outward, remove items. Close it normally and check your panel's start control before making one permitted retry.
When the latch seems correct
A mechanical click does not guarantee that the control recognizes the lock. Note whether the warning appears immediately, whether the cycle starts, and whether the door remains held shut. If E16 returns with the latch free, request service.
See door and safety issues if the problem is opening after the wash. This interpretation applies to washing machine E16; it does not assume equivalence with F16 or with codes from other appliances. Confirm the unit's E-Nr.
Do not bypass the latch or insert objects to simulate a locked door.