Milner safes with the chevron keyway, also old Ratner safes and some Whitfield too. The key only goes into the same position that it came out of. Normally when locked, you put the key in at the 7 o’clock position, turn clockwise to unlock. If you usually leave the key in while the door is open, then you only ever use the 7 o’clock slot. If one day someone unlocks the safe and takes the key out, then sometimes people try to put it back in at 7 o’clock to lock. All you need to do is put the key in with the bit (aka flag) pointing up to 11 o’clock and it will go in further and lock normally again.
Another common reason that safes do not shut easily is getting something trapped around the door edge or in one of the bolt receivers. Do not force the door closed, if you cannot see what is wrong then call a professional. Safes that don’t close are a lot cheaper than safes which don’t open! Ratcliffe and Horner. Whitfield.