The most common cause of this problem is the carbon brushes on the motor.
There are other causes such as a faulty motor or faulty control board but these aren't quite so common.
You will need Torx drivers or bits to take the screws out.
Unplug the appliance.
Take the rear panel off.
Check the wiring to the motor plug and the motor plug.
If ok, take the motor out and check the carbon brushes on the motor,
(You will likely need to drop the motor onto the floor and tilt the machine to get it out, if there's no solid base on your machine. Don't put the machine on it's back, side or upside down).
If worn out or broken, you'll need to fit new ones.
If all is well, when refitted the machine should work normally again.
Check it out, see what you find and get back to me if you need more help
If the carbon brushes aren't worn out or broken, the motor and/or control will be at fault.
Obviously, if you cannot do the work yourself, you'll need to call in the engineer.
Check it out, see what you find and get back to me if you need more help.
Don't rate my answer until you are happy, just use the reply to get back to me with further questions.
Hope this helps
Let me now how it goes