SSRS Report Viewer not showing report

I am using an SSRS Report Viewer web part. When I place the path to the report server in the "Report Manager URL" box, then click apply it shows an IFrame with an index listing of all my folders. The next thing I do is take one of the folder names - "Public" and a report under that folder "otd" and place that path in report path: /Public/otd. When I click apply, it still shows the index listing page. Why isn't it showing the report i gave the path to? This is running native on SharePoint 2013 on premises install.