User blog comment:B214/Chapter 497: The Winter Mage/@comment-14.201.211.143-20160809020614/@comment-14.201.211.143-20160809024751

Maybe Neinhart cannot revive Enchantments because their don't die just lose their link to an object. Irene has a lot of her conentration on removing FH so she might be unable remove Erza's magic.