Security Blockade — ruling 1

You must target a land to cast Security Blockade. If that land is an illegal target when Security Blockade tries to resolve, it won't resolve and won't enter. You won't get the Knight token.

Security Blockade : règles, fonctionnement et interactions (MTG)

Security Blockade is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Enchant land When this Aura enters, create a 2/2 white Knight creature token with vigilance. Enchanted land has ": Prevent the next 1 damage that would be dealt to you this turn."

How it works : Security Blockade

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2012· Wizards of the Coast
You must target a land to cast Security Blockade. If that land is an illegal target when Security Blockade tries to resolve, it won't resolve and won't enter. You won't get the Knight token.
Card named in this ruling
Knight