Do basic troubleshooting:

• Disable Pop-up Blocker
• Clear cache and cookies
• Chrome preferred browser, but any updated/latest version of a browser can be used.
• Ask the user to log out and log back in. 

Should the issue persist, ask the user to take a screenshot of the error message they're receiving or the slide they're stuck on and submit a ticket. In your ticket, be sure to include the troubleshooting steps and the screenshot.