Fuel sending unit not flowing.

I have a brand new sending unit installed into a brand new tank I cannot get fuel to come out. I thought it was a fuel pump issue (also brand new) so I hooked up a electric fuel pump, nothing. So I thought maybe it was a clogged line so I unhooked the fuel lines and connected the electric fuel pump straight to the sending unit. Still nothing. I know the tank is full. It's like it's stopped up no air or gas is coming in or out. I even tried to blow compressed air into the sending unit to "clear the clog" still nothing. I don't get it! Anymore ideas I can try before dropping the tank again?