Don't cancel, @Didier90! When a host cancels a reservation, they incur lots of penalties which can be very difficult to deal with. If the guest has not cancelled, they are still liable for the cost of the stay, in keeping with whatever cancellation policy you have chosen. Make sure you communicate with the guest ONLY through AIrBnB. Contact AirBnB by using the link on the reservation tab on the AIrBNB app, to let them know what is going on and see if they have any further directions for you.
Good luck. Let us know what happens!