Filler not working for new ranks menu using deluxemenus

I have a new ranks gui menu using the dm plugin. I'm working on the filler and just copied and pasted the same code from the same plugin on a different menu and it's not working for some reason. Any help? This is just a snippit of the gui but the filler code is down below '7': material: NETHER_STAR amount: 1 slot: 16 display_name: '&8◆ &7(&9Enderdragon&7) &8◆' open_requirement: requirements: upgrades: type: has permission permission: rank.IronGolem output: true lore: - '&7Click to purchase the &9Enderdragon Rank&r&7.' - '&r' - '&7Perks' - '&7* Inherits from IronGolem' - '&7* Ability to set 10 homes' - '&7* Access to /heal' - '&r' - '&eCost: &55,000,000 &e⛃' left_click_commands: - '[console] eco take %player_name% 5000000' - '[console] lp user %player_name% parent add Enderdragon' - '[message] &a(!) You have successfully purchased the &9&nEnderdragon Rank&r&a.' left_click_requirement: expression: '%vault_eco_balance% > 5000000' filler_item: material: GRAY_STAINED_GLASS_PANE display_name: ' ' slots: - 0-9 - 17-27