cant unban players

So i banned my friend to troll him from my 1.8.8 aternos server and like 3 days later i tried to unban him but in the console it said issue command or something like that i cant unban him , his ip , from the console , in-game and from the banned players tab in aternos. Here are all the plugins my server has and thanks in advance for the answers(customchatprefix, essentialsx, luckperms, nametaghide, seeplayerinventory, skinsrestorer, supervanish, unbreakable, worldedit,worldguard, idisguise)