2008 Prius, keyfob stopped working

Keyfob stopped working for no apparent reason, I changed the battery and checked the button under dash. Red light on keyfob goes on but car doesn't recognize it at all, even when placed in the slot. I don't have another key. Everything else seems to be working properly. When I place the keyfob in slot red car light key flashes on dash but nothing happens.
Any ideas?
Thank you

 

Update: I long pressed the panic button while inside the car and the fob now locks/unlocks the car but still can't turn it on