@Pamela619 What happens is: at the point when the guest places a long-term booking, Airbnb only collects the first 30 days upfront. After that, the payments are scheduled on a monthly basis.
So the problem here is that at the time the guest placed the booking, Airbnb does not require the funds to be available in their account for more than 30 nights' booking charge. Even if the guest doesn't cancel early, it's possible that on Day 31 you receive notice that Airbnb was unable to collect payment for days 31 to 60 - at which point you're permitted to terminate the booking but you don't get your payout. * And that right there is the no. 1 reason I don't think Airbnb is a valuable service for long-term bookings. It is very easy for the host to get screwed, and since you can't hold a deposit you don't have much recourse aside from suing the guest for breach of contract.
The problem could actually be something as simple as the guest needing to manually authorize a charge on her bank card or change the selected payment method in her Airbnb account. It's also possible that she's attempting an Extenuating Circumstances cancellation, and Airbnb is putting the payout on hold while investigating. A third possibility is that the next payment is scheduled for the 30th day of the booking and the cancellation hasn't triggered it to be updated. And finally, it could be just what Airbnb said it was - for whatever reason (no funds in the account, etc) the guest's payment method could not release funds to Airbnb.
* One hack that might work for those considering long-term stays: if you want to bypass this issue, you can require that the guest break their stay up into blocks of 27 days, thereby reverting to your normal Cancellation Policy. This could mean you're entitled to less compensation in the event of an early cancellation, but on the other hand it would ensure that Airbnb has collected the payment before the booking begins.