Although you posted in a topic that sounds similar to the issue you’re having, it actually is not. In fact, no one else has reported the problem you’re reporting. The reason this is important is that it narrows down the troubleshooting to there most likely being a specific issue in your setup and not an issue in WP, the theme or the plugin, although that is still possible.
Next, we’ll want to check that everything is up-to-date, WordPress, theme and plugins?
You’ll also want to just double-check the instructions again:
https://startupwp.com/topic/setting-up-the-slider/
If it’s still a no go, at that point, it’ll probably be easiest to get your login info privately by email and then investigate directly. If necessary, do we have permission to request info and access by email?
Thank you.