Socket not working

I have an item that will not let me put runes in it, here is a Copy-Paste of the item.
It's not a fancy item but I would still like to be able to use a rune in it.

Item Class: Sceptres
Rarity: Rare
Honour Song
Omen Sceptre
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Quality: +20% (augmented)
Spirit: 135 (augmented)
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Requires: Level 66, 46 Str, 117 Int
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Sockets: S
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Item Level: 71
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Grants Skill: Level 16 Malice
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35% increased Spirit
Allies in your Presence have 23% increased Critical Damage Bonus
Allies in your Presence Regenerate 13.2 Life per second
52% increased Presence Area of Effect

Checking with Exiled Exchange i get this in reference to the socket.
Sockets: S
Sockets: S
explicit — Not recognized modifier