I have an existing Craft Pro installation (v2.5.2757) that I'm using to drive an application. The current install does not have a homepage or any entry associated with a URL. All requests are being handled by Dynamic Sites Routes (routes.php).
The site has been running without issue for months with edits being made to entries and content being updated in the application.
However, when I went to create a homepage for the site, I would receive the following error when the site loaded:
I confirmed that the 'This is for the homepage' was checked and that the correct 'Entry Template' was entered. I suspected that something in routes.php was causing the issue, but cleared that out and still received the error. I tried clearing the caches as well but no luck.
After multiple hours of troubleshooting I'm at a loss.