The part cant unfold or flatten

Hi guys so I am working on a project for a university and need to make some things from sheet metal. I am new to this modeling with sheet metal but I kinda get what is all about.

So I started to work on this part and I am sure that lines dont intersect but still I cant unfold the part.

Can you help me ? What did I do wrong?

Thanks a lot,

Branislav.

SolidworksSheet Metal