I'm getting a mostly blank screen when trying to run reports. I see the CiviCRM menu and page heading, then the page footer, with nothing in between.
I get the same thing for every report and every report template. The "Manage Templates" screen works, but if I click "Edit" on a template, I get a pop-up with no content.
I have no errors in the CiviCRM log file, no errors in my PHP log file, and no browser console errors. This is CiviCRM 4.6.26.
What steps can I take to further troubleshoot this problem?