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I presume there are no error messages showing on the console.
How old is the Crosswalk treadmill machine in question?
Was there ever any problem with the Crosswalk before this happened, or was it simply that it one day failed to move the walking belt ?
If there is no error message and there were no problems before this, then how recently did you adjust the tension on your Crosswalk's walking belt?
If the tension is not adjusted regularly, to be basically speaking just loose enough to not slip when walked on, then the belt may dry up and tighten up over time (esp. if lubricant is also not applied regularly - note that the lubricant is a special silicone-formulated lubricant, and grease or oil -based lubrication will destroy the belt's fabric, in case it needs mentioning...)
If the belt tightens up for years, eventually it will place stress on the moving parts, and also on the motor. The motor may eventually burn out its windings from this stress, over years.
Your case does sound rather like one where the motor windings have burned out. But! it's possible that it is some other major failure, that could be revealed and treated by removing the covers of the machine and examining connections, parts, indicator lights, etc. The motor controller board, too, can become defective (though the symptoms are usually different from the simply-not-moving case which you are asking about.)
Let me know how you'd like to proceed, and I will help you further with this problem. Thanks.