I am using the version for Fabric 1.21.1 and I'm trying to make a rectangle border but when I do its not solid and I can just walk right through it, I also tried to get the border wrapping to work and it also didn't do anything

If you are a server operator or are in singleplayer using cheats, you will have border bypass permission by default. You can fix this by using LuckPerms and configuring the permission, or not giving yourself or anyone not supposed to go through the border op/cheats.

If you have any other questions about using chunky please join the Discord! Happy to help more there in case you have any problems.