Index never loads with WebHelp Pro 2015 project published to RoboHelp Server 10

I have a project that has been upgraded to RoboHelp 2015. If I view it using the viewer inside of RoboHelp, the index is there. When I publish this project to the RoboHelp Server 10, it continuously has the words "Loading index" on the index tab as shown on the screen shot.

The index never appears. If I publish this project to RoboHelp Server 9, the index works fine. If I generate and publish a responsive HTML5 layout with this same project I get the index. I'm having the same issue with all WebHelp Pro projects I have published to RoboHelp Server 10.

I'm out of ideas what to try next.

Thank you,

Nita