Bluetits disapeared


I am new here.

We have had a bird box on the side of our garage for years and never had anything nest in it. This year we have been really excited to have Bluetits nest. We have been fascinated watching their journey from building the nest, pecking around the entrance hole (why do they do that? they could fit in already anyway) and then eventually lots and lots of visits to and fro all day in and out and we heard chicks chirping. We first heard the chicks about two weeks ago maybe a bit longer.

Now, more or less overnight, nothing. No parents visiting and no chirping from the box and no sign of them anywhere in the garden. We were so looking forward to seeing the babies emerge. I was told that when its time the parents would encourage them out and they would hang around the garden for a while before moving off. We've not even seen a chick pop a head out. Everything seems to have stopped so suddenly.

I'm worried that maybe something happened to the parents and the chicks have died inside the box. Should we check inside?

Any thoughts/advice would be appreciated thanks