Can you create a NEW test page based on the default template
Above the Page content editor you should have a button “Add Show Slider” (same line as the “Add media” button)
When you click on that, you should see a drop down list called Select a Slider.
When you open the drop down list the slider you created should be in the list, you select it and click Add.
After you do that, you should see the shortcode in the page content editor inside its square brackets.
If all that goes as expected, give us a link to that test page. If any of these steps do not match what you see, please elaborate