Using Greater Essence of Torment on a magic item with 2 runes socketed inside

Trying to use a Greater essence of torment on a magic 2 hand maul that has 2 iron runes socketed inside of it. I get the message "failed to apply item: Items sockets are not empty."
The maul has a prefix and a suffix, it is not corrupted
https://imgur.com/a/kWDRAw2