Kathy the cause could be radio frequency interference (RFI). I've had and still have the issue at certain locations.
For example, at my local train station they have a lot of electrical "stuff" behind a chain link fence. When I'm there in the parking lot I get the message that my key is not present. However, my car still starts. I can't open or lock the doors with any certainty. I have to use the key fob or key pad.
Does it always happen to you at the same place? If you leave the location and come back does it still happen?
You're not doing anything wrong it's just physics. If you look at page 48 (Keys and Remote Controls) of your 2014 MHZ owners manual they have a discussion about this issue.