2016 Model S 85D and never had this happen. I drove about 2 miles, then used AutoPilot about 1 mile of that to hold to speed limit going down a 10% grade. Drove another 2 and stopped at a store. When I came out, a message saying AutoPilot was unavailable until maybe after next stop (my paraphrase) and this switched with Adaptive Cruise not available. I understand if you don't respond to the AutoPilot warnings to apply pressure to steering wheel, you can get locked out of AutoPilot, but I never got any warnings and the lockout came after the car was stopped for 5 minutes. I tried driving a short ways, stopping, waiting 5 minutes and nothing helped. I tried turning AutoPilot off and back on, but no change. It only came back after I had driven 120 miles and stopped for lunch (about 30 minutes). Behaved properly since. Something I did, random bug, suggestions for getting to it return to normal? Not having Autopilot available is really a pain.