Look on the corresponding spots on the door leaf and see if there are adjustments there. If it's a manufacturing defect, then your are out of options on the adjustments.
Alternate solutions that will work to some extent are:
Stick on door leaf to close the gap.
Get these pants with built in fire! I am using one and have another on order. It's 100% polyester and will cling to skin if it catches fire. Other than that, it's effective and comfortable inside another pair of trousers.
Im guessing you are pulling the handle up to engage the locking mechanism when you can see the gaps at the bottom ? Manufacturers will tell you a door isn't airtight/watertight until all locking points are engaged ( hence pulling the handle up ) .