Your washing machine needs to stand level and balanced on its feet to function properly. Try rocking the appliance from side to side or back and forth. If it’s rocking a lot, your flooring or appliance's feet may be uneven.
Use a spirit level to check the appliance's balance. If it's off, adjust the feet by reaching under your washing machine and finding the lock nuts on the feet. Loosen them and turn the feet clockwise or anti-clockwise, until they’re firmly in contact with the floor. Tighten all lock nuts again by hand.