Ford Repair Questions? Ask a Mechanic for Answers ASAP
It sounds like the vehicle's security system isn't recognizing your key and allowing the vehicle to start. Do you have a spare key that you could try?
If not, you may have to have the security sensor replaced or reprogrammed. If the spare key doesn't work, then you know the transceiver that picks up the signal from the key is not working. Reprogramming keys on this vehicle requires a specific scan tool, so you might call around to local lock smiths and see what they would charge to program it for you. It would be a lot cheaper than the dealer.
I can send diagrams of the security system components if you plan to tackle it yourself.