You may see the following error message from Disqus when viewing a Disqus lesson:
"We were unable to load Disqus. If you are a moderator please see our troubleshooting guide."
If so, take a look at Disqus' troubleshooting guide.
The most likely culprits are 'Disqus is being loaded on a non-trusted domain', or 'Disqus is being loaded on a different domain than you registered'. To fix this, you will need to set up your Thinkific site as a trusted domain by adding either thinkific.com, or your custom domain if you're using one (e.g., yoursite.com), to your list of trusted domains on Disqus (here's how).
Alternatively, if you've recently changed your Thinkific domain, installed a custom domain, or changed your Disqus lesson titles, chances are your course player is no longer able to load the Disqus discussion.
This is because the URL has changed and Disqus doesn't know how to connect anymore. You'll need to remap the URLs in Disqus.