When I try to add the list, I paste them, click save, and I get a 403 forbidden page.
But when I do something else on the page, click save, I don't.
Its your host. they are censoring the content that you send. theyre basically blocking you from typing words/phrases they do not agree with... for "security" lol
refer back to your other post when you had the same problem
https://www.ubbcentral.com/forums/ubbthreads.php/topics/265214/403-forbidden