Thank you for contacting Adobe Captivate Prime Team.
This looks like some issue with the content loading.
If possible try to close the course and try to re-start it and check if it's working.
If you are getting the same issue there try to use another browser if possible.
If the issue shows up in both the above cases, kindly reach out to your Captivate Prime account Administrator to look into the issue. If required your administrator can reach us to get the content checked.
We do not have access to the contents that are uploaded to the account. We need the help of the account admin to troubleshoot this issue.