We got it figured out! In the 'view this email in a web browser" link at the bottom of your campaign, there was a space after the tag [% webview_url %], which lead Emma to believe it was an actual URL and she added the http:// before the tag. Remove the http:// and the space after the tag and you should be good to go to send a test.
That should do the trick! Feel free to reach out with any questions or if there is anything else I can do to help!