Since the oven would not light but all the burners and broil worked fine, it likely was the oven igniter or the solenoid gas valve. I called LG and asked them specifically what error message F11 meant. They told me F11 meant not getting gas and needed a repair. They were happy to give me the authorized LG Repair services in my area. When I went to the AppliancePartsPros.com website and looked up the igniter, there were several people who said they got the F11 error message and it was the igniter. I removed the sheet metal parts that covered the igniter and tried to start the oven again. The igniter did not heat up and turn orange, so I bought a new igniter and replaced the old one. At 73 and not so nimble, it took me longer than most but it was not difficult.