Does the preview survey do not display results?

The error you’re experiencing while trying to download results in Qualtrics during the preview phase may not necessarily reflect how your reports will look when your survey goes live. Previews are typically used for testing purposes and may not generate complete or accurate reports.

Remember that issues encountered during the preview phase may not necessarily reflect what will happen when your survey is live.
but can conduct a real test run, this will allow you to verify the data collection.

What is the best way to check if the results will be rendering fine on the main survey then? Any suggestions? Thanks!

You could try publishing the survey and using the anonymous link to test the survey. Just make sure to delete all test responses before launching the survey.