I am playing on a private server and I want to expand my TARDIS to have lots of rooms and such, but I am locked from going outside the specified area. If I try and break the barrier blocks, it says "Cannot Interact outside of your TARDIS". I checked the configs and found 'TARDIS Boundary Generation' but it is false, so I'm not sure how to fix this, any help would be appreciated!

Go into the Dalek Mod config and disable the Tardis Griefing option, this will allow you to expand outside the default area. You can also increase the interior generation size to give you a bigger area to work with