Hi as you have identified the E106 error relates to the door lock mechanism and sensor.
1. Locking hook blocked Check bar and bar receiver for blockage
2. Check the plug and socket connection for corrosion\being lose.
3. Failure in wiring check wiring and continuity.
4. Micro switch is in correct position on frame
6. Micro switch is not short\open circuit
On the right side of the door recess there should be a locking bar that comes out. This bar may well be stuck, causing the problem.
It's the most common cause of the error code. The machine is detecting it's in the wrong position.
Out of all the items I think the most likely fault is the micro switch, which is just a case of testing the continuity as you manually activate it.
No problem Hugh, its often a case of trial and error.
Glad you have identified the fault.