Spell input lag issue

My friend and I are in Taiwan. And he was experiencing unplayable lag lately. Basically his spell will come out like 20 -30 seconds after he finished his clickings. But basic attacks seem alright. He switched to different clients and it's not helping (Lunar, vanilla, wynnstils, etc). Is there any way that can fix this problem?

 

Could be the world you (or your friend) playing on is having lag issue too. You can easily see which server has lag or not in /lobby, and pick the recommended one.

But bigger chance that its really just basic connection issue between countries