It sounds like you've accidentally blocked those dates. If that's the case, tap on the dates in question to unblock them; otherwise, contact Airbnb support.
I think you may have activated days that guests can't check-in or out via your calendar. Remove the days that have been ticked and this will free up your calendar and that "host not available" should disappear.
I'm seeing the 19th June as only a check-out date possible but all the other dates are OK with only a 1 night minimum for guests.