Chances are that your guest has paid. Sometimes it takes a few business days for the money to be depositied into your account. Did you receive the standard message stating that funds have been deposited?
Well, I understand it takes few business days that the actual paid amount has transferred into my bank account. But mean while, I used to receive an email notice from Airbnb that "payout of $*** sent" one day after guest's check in.
But in this guest's case, I haven't received the email notice even it passed two days from the guest's check in.
@Chuck76 What does it say under transaction history in your account for this reservation? That's the first place to look. It should say pending, or released and if pending, will show the projected release date.