Outline.nvim: (outline) No response from provider when requesting symbols!

https://github.com/hedyhli/outline.nvim

When I do :OutlineOpen on a markdown file it says (outline) No response from provider when requesting symbols!, when I do so on a Lua file its blank. I have LSPs installed for both. I don’t have any configuration other than require("outline").setup({}) in my init.lua, am I supposed to? the repo page shows the defaults and LSP is on there.