OpenSearchServer Renderer is empty

Question

When accessing my renderer in OSS and searching for something it shows me how many files where found and from what type, but it does not show me the files itself.

The page is empty for some reason (looks like this: https://i.stack.imgur.com/2k8mN.png)

Answer 1

I forgot to add fields in which the renderer will display my results. Renderer > Fields was empty.