Newbie here!

What I am trying to do:

I am trying find stress and deformation in static pressurized vessel.

What problem am I facing:

One face of pressurized part is bulging in a different direction. Even though stress and deformation has about 2 F.O.S but the way it is deforming is wrong.

Can you help me to find out what is causing that issue?

Edit:

Since the pressure is internal, the bulge should have towards outer side like balloon but the structure caves in in the upper side.