I generated a very simple responsive page in the just-released Muse 2015.1. Created an article with the HTML article packager. The article displays perfectly in my app on iOS tablet and phone, and Android tablet. But it just shows up as a white screen in the Web viewer. You can see it here http://adobe.ly/1SNVPnO (select the How-to: Outdoors article). Is this a known issue? FWIW, I'm using self-hosted Web fonts for my text in Muse if this makes any difference.
Please try to change something about the article and re-upload it. A simple way to do this would be to re-upload the article image, though it could be the same image. After doing so, please republish the article. There was an issue in the upload process of some articles that some files within the upload were malformed, but it has since been fixed. The above steps should rectify the issue.