Server not starting, incompatible types

[nadavhames]

When I try to run the server, I get the following warning 4 times in different areas of lib/riverside.ex. It finishes generating the app but then it does not run. Maybe this is an obvious bug, but I am quite new to Elixir so some help here would be appreciated! Thanks

Compiling 3 files (.ex)
warning: incompatible types:

    map() !~ Riverside.Codec.JSON

in expression:

    # lib/riverside.ex:955
    %{codec: Riverside.Codec.JSON, connection_max_age: :infinity, idle_timeout: 60000, max_connections: 65536, path: "/", port: 3000, reuse_port: false, show_debug_logs: false, transmission_limit: [duration: 2000, capacity: 50]}.codec.frame_type