Hi,
How old is the fan?
According to the [https://www.vornado.com/wp-content/uploads/2016/04/X60Series.pdf|user guide] there is a ''5 year manufacturer’s warranty'' on the fan.
If the fan is not that old, contact the manufacturer as per the warranty statement in the user guide.
If it is older than 5 years, then the fan speed controls would be the first place to check as it may be a problem in the speed button assembly or what they connect to.