I just got a pod server set-up - v5.5.2 on Windows 10, Node v12.18.3
When the registration processed is finished, it automatically sends me to my page.
(from https://solid.example.com/register to https://rogerfgay.solid.example.com/) // fake domain
Then I get the error message in the browser and nothing else.

Path must start with hostname (/rogerfgay.solid.example.com)

config: "root": "C:\programs\solid\data"
directory C:\programs\solid\data\rogerfgay.solid.example.com exists and has a lot of normal looking stuff in it

Server-side:
solid:get / on rogerfgay.solid.example.com +0ms
solid:get GET -- Error: undefined Path must start with hostname (/rogerfgay.solid.example.com) +1ms
solid:server Error page because of: Error: Path must start with hostname (/rogerfgay.solid.example.com)
at ResourceMapper.mapFileToUrl (C:\Users\roger\AppData\Roaming\npm\node_modules\solid-server\lib\resource-mapper.js:77:15)
at LDP.get (C:\Users\roger\AppData\Roaming\npm\node_modules\solid-server\lib\ldp.js:358:10)

note:
resource-mapper.js, line 77
path is C:/programs/solid/data/rogerfgay.solid.example.com/
/${hostname} is /rogerfgay.solid.example.com

!path.startsWith(/${hostname}/)

SOLUTION? (This is my first time in, but it looks something like starting comparison at the length of the root?)
!path.startsWith(/${hostname}/, length of root)