@Krzysztof23,
Dates can appear blocked for several reasons , i mention some of them:
- you cancelled a reservation for those dates (dates can not be unblocked)
- A reservation request was declined by you for reason: dates not available
- A reservation request was not accepted or declined within the time limit
- Dates are outside the "booking window" (which can be set)
- Dates are blocked manually by the host
- Your listing setting is: dates are unavailable by default
- And offcourse: when there is a reservation or a request on those dates
etc..
https://www.airbnb.com/help/article/447/how-do-i-make-dates-available-or-blocked-on-my-calendar
Best regards,
Emiel