In order for a list view to show up on Owler.com you may need to make one adjustment in Salesforce.com. 

Go to Salesforce and click on 'list view controls' on the list view you would like to see. Once this drops down, then click on Sharing Settings.  

You want to ensure that you have 'All users can see this list view' selected. 

Once this is complete you should be able to see your custom list view on Owler Pro.