Newbie problem. Why does my bread collapses?

Guys I've just started making bread. Why does it fall like that?

I have used the following ingredients:

350ml of water 2 tablespoons of olive oil 200g of whole wheat flour 100g of rye flour 100g of chickpea flour A bit of salt 6g of dehydrated yeast

The flavour is good but I can't make the loaf to stay up. I have tried halving the yeast and nothing changed.