FIXED, okay for anyone who has this issue and stumbles onto this forum what you have to do is:
Go to the plugins menu and install mcedit and WorldGuard.
Now make sure you have op, go into your server and into the dimension you want to enable the spawning and type in “/rg flag __global__ deny-spawn ZOMBIFIED_PIGLIN”
This works ONLY in the dimension you use it in, this also works for any other mob including bosses. Date is February 5,2021 Minecraft 1.16.5
