I am receiving weird error while attempting Test Callout (#5), it is giving below error.

Challenge Not yet complete... here's what's wrong: 
The 'WarehouseCalloutServiceTest' class does not appear to be using the 'WarehouseCalloutServiceMock' mock callout class.

But my WarehouseCalloutServiceTest is calling the mock class and it shows 100% code coverage for WarehouseCalloutServiceMock class after running the test. 100% coreage for mock class shows that I am using the class. So,  Can anyone help in figuring what can be the issue.

Hi Guys 

I have implemented the below class and also scheduled it . 

Still getting an error. 
Challenge Not yet complete... here's what's wrong: 
The Apex class does not appear to be implementing the execute() method.
Very sad to see was not able to complete in the first attempt after making everything right.

public class WarehouseSyncSchedule implements Schedulable {
  
    public void execute(SchedulableContext SC)
    {
        WarehouseCalloutService.runWarehouseEquipmentSync();
    }
    
}