It is possible the blade is not attached tightly to the cup. Remove the cup and blade from the motor base, tighten and reattach. 

Alternatively the seal within the blade attachment may have dislodged from its position or damaged. If so a new blade can be purchased below. 

• Australian customers click here to purchase accessories.
• New Zealand customers click here to purchase accessories. 

Not sure what machine you have to purchase compatible parts? Click here.