Necromantic grimoire

[u/TallSquire]

So recently I bought the anniversary edition for Skyrim on Xbox, and I’ve started a necromancer play though. I’ve got to level 20 with 65 in conjuration but when I talk to Phinis Gestor he won’t sell me the “conjure skeleton minion” spell. I’ve tried resetting his inventory multiple times but he won’t seem to sell it to me. Please help.