One worked, one did not

I just received these diffusers in the mail today I got them for my daughter who has epilepsy I figured the light would be nice as a nightlight and putting lavender would help her seizures I plugged in one of them and it works fine it's quiet and the diffusion works great! I plugged in the other and it is very loud and has this annoying clicking sound so I will have to return it :/

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