Having problems for the Task - Enchant and Earth Tiara on an Earth Altar.

I have all items - the earth tiara ,rubys and saphires if needed , Earth talisman ,water & cosmic runes for the enchant spell, and Im standing inside the Earth Altar ,but when I click enchant on earth Tiara - I get a message saying - "can not enchant that item" , please help. What am I missing ?

To make an earth tiara you use the talisman on the altar with a tiara that’s plain in your inventory if I’m not mistaken

thank you