Xavi, yours is a house rule. Look at the last sentence of the second paragraph of the spell description. Or look at the first bullet point for spells here: https://forum.atlas-games.com/t/a-guide-to-aegis-of-the-hearth/6092/1 .
Fixer, I would combine the penultimate sentence in the second paragraph of the spell description with the ultimate one. The penultimate one says a spell that fails to penetrate "fizzles out" and the ultimate one says spells like the one you mention must penetrate, so it seems such a spell should fizzle out. So I don't see any basis for the first of your three possibilities. As "fizzles out" isn't very specific, it's a guess past there, but I would go with your second interpretation over your third since to me "fizzles out" seems more like "extinguished" than "suppressed."
Chris