The tourism authority (JTA) had set a deadline of June 15 to do this, and those who hadn’t received a license by June 1 had to cancel reservations booked before June 15, and Airbnb has extended this to cover the gap of other travellers so that they have time to make alternative arrangements:

The $10 million fund, Airbnb said, will cover “additional expenses for guests who are scheduled to travel to Japan and have had their plans interrupted due to a cancellation.” Those whose reservations are cancelled on or after June 15 because of the license situation will get a full refund and a coupon worth “at least 100% of the booking value” to use on a future Airbnb trip.
Due to a change in Japanese legislation, Airbnb announces that it will be cancelling thousands of reservations made in the country.