Why is my mixer making a very loud vibrating noise on higher speeds

Why is my mixer making a very loud vibrating noise on higher speeds

I have a Kitchen Aid Artisan Mini, it’s only a few years old and I don’t use it very often/intensively. Last time I used it, as I turned up the speed above 6 it suddenly started making a very loud noise and started vibrating so much that it was moving along the counter a bit so i quickly turned it off. I tested it again without any bowl or mixer attached and it did the same thing.