New lighting fixtures to old wiring
The fixture needs black to black, white to white  and  ground to the mount or electrical box.  If this doesn't work, then you have an open neutral somewhere in the line and you need to find out where it is. You'll have to check everything on the circuit to determine where the open neutral is.  Do not keep the white wire connected to the mounting bracket (which is probably grounded),because you're completing the circuit through the ground path, This is dangerous, it could kill you.