Generated configuration files have ports in their host specication
Specifically:
config :pleroma, Pleroma.Web.Endpoint,
url: [host: "localhost:4000", scheme: "https", port: 443],
This makes phoenix detect the address as IPV6 and create obscure errors when trying to request the base address, because it looks like http://[localhost:4000]/
(IPV6 addresses require/allow brackets, IPV4 dont).
Edited by vaartis