This has happened to me a few times now. After turning the ignition off for a short time I am unable to put the car in gear when restarting. The button on the side of the shift lever will not push in, as though a lock is not releasing. So far by waiting and trying again repeatedly I have been able to drive again. I don't think this has ever happened when I first start the car in the morning.
Transmission "sticks" when restarting. on 1997 Lexus ES300
Around the gear shift lever there is a small black rectangular plug you can rove that and use a key or small screwdriver to "over ride" the gear shift lock. I suspect the solenoid control or circuit that prevents you from starting the engine in gear. Sometimes they stick if coffee or liquid has been spilled around the shift lever.