@Jeanette141 It's not a great idea to block dates for an inquiry, unless for some reason you really want this guest and are confident that they're serious about booking. Many guests send inquiries and even if you respond with a nice, welcoming message, you never hear from them again. It's not that they didn't like your place or your message- they may have sent out inquiries to 10 different places.
You don't have to either per-approve or decline an inquiry- all you have to do is message the guest back within 24 hours. Then, if you clear your cache, the annoying messges from Airbnb to pre-approve or decline will stop.