Single wall oven. error code: c75 comm error. door engaged show on screen, cam sw, lock sw and door sw are open, but can't open the door.

Just guessing but did you just use the clean cycle???? During clean, the oven temp gets high enough to trip the door lock safety thermostat. This is to keep owners from trying to open the door when oven is too hot from clean cycle. It sounds like that safety didn't reset to normal when it cooled off and therefore the door is still locked. With door locked you may need to get oven out of the wall and remove top cover to get to the lock system and thermostats. Make sure power is off before doing any of this.

This is what I used on my Kitchenaid Superba maybe it will work on yours also.
Hold the "oven light"
then push the "CLEAN" button
and then the "START" button.
Wait until "Door Locked" shows on screen.
Press "Cancel/Off" (Upper Oven) wait until "Door Locked" turns off.
The oven F5 E1 is now fixed.

Error Code E90 typically means that you have a faulty motor door latch, lock motor assembly, door light switch or a defective EOC. You would need this to be diagnosed by a professional technician in order to properly repair the wall oven.

Communication and timed error with the door sensor.

check for loose connection on the door sensor or micro switch you ay need to change the micro swich if faulty

Open circuit in the door contact switch even if the door is locked.
If this happened during a clean cycle sometimes if you start another cycle and then switch the selector off after a few seconds the fault will right itself. If this doesn't work then you probable need a new door lock.
Hope this helps

have to have a repairman come out and reset the code on the inbord computer not a simple fix i know i sell appliances

Lock disengaged on its own after a day. Oven is now clean, everything working properly.

oven door will not close tight - what is wrong

My oven was locked and would not open. No lock light was on but the oven was clearly locked. F9 error when I hit certain buttons.

Try this. I unplugged the oven for about 5 minutes. Plugged back in. A LOCK light came on. Held down "Oven Cancel" for a few seconds. Door opened and lock light went off. No more F9 error when I hit those buttons.