The belt may be too tight or in need of some lubrication, or the motor may have failed.
First, try running the machine with the belt loosened.
If it still doesn't work, then test the motor by connecting a power supply directly to it. If the motor does not run normally then it will need to be replaced.
If you need the contact details for a repairer in your area, please let me know the zip code.
You can test the motor using a battery - see this video guide: https://www.youtube.com/watch?v=sdR4JGcygnQ
If the motor does not work when powered by the battery then it will need to be replaced.
You don't need to worry about the control wires on the motor - just connect the two power wires direct to a battery to test the motor.
If the motor is not working then it will need to be replaced.
We are not looking to run the Ac motor, just check if it turns briefly under DC voltage which is much safer.
However, you can test it using AC power if you wish, however you must take care when working with the dangerous live voltages.