Need Appliance Repair Help? Ask a Technician for Answers ASAP
Do you see a pad lock symbol on the display board or does it show LOC or Lock or anything like that on the display?
F90 means that your door latch assembly has failed. That is why the oven won't work. Unfortunately the latch has just failed and would need to be replaced to resolve the error and then you can use the oven again. This is not an issue you can just reset.
We are on the honor system here. Please remember to rate my service by selecting a star at the top of the screen before you leave today. If you need anything else, just let me know. You can continue asking follow-up questions at no additional charge after rating my service if you still need assistance.