Icecast2 fails with error mopidy.audio.gst GStreamer error: Could not connect to server

I have been trying to get network streaming working via icecast. I keep getting the error [MainThread] mopidy.audio.gst GStreamer error: Could not connect to server.

I get the error when I play music from Spotify and local media.

I am running this in a proxmox container.

I have added the fallback stream config.

  <mount>
  <mount-name>/mopidy</mount-name>
  <fallback-mount>/silence.mp3</fallback-mount>
  <fallback-override>1</fallback-override>
</mount>

Mopidy:

/usr/bin/mopidy --version
Mopidy 3.0.2

icecast2

/usr/bin/icecast2 --version
Icecast 2.4.4

OS

lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04 LTS
Release:	20.04
Codename:	focal
sudo mopidy deps
Executable: /usr/bin/mopidy
Platform: Linux-4.15.18-28-pve-x86_64-with-glibc2.29
Python: CPython 3.8.2 from /usr/lib/python3.8
Mopidy: 3.0.2 from /usr/lib/python3/dist-packages
Mopidy-MusicBox-Webclient: 3.1.0 from /usr/local/lib/python3.8/dist-packages
  Mopidy: 3.0.2 from /usr/lib/python3/dist-packages
  setuptools: 45.2.0 from /usr/lib/python3/dist-packages
  Pykka: 2.0.2 from /usr/lib/python3/dist-packages
Mopidy-TuneIn: 1.0.0 from /usr/lib/python3/dist-packages
Mopidy-Mopify: 1.7.3 from /usr/local/lib/python3.8/dist-packages
  ConfigObj: 5.0.6 from /usr/local/lib/python3.8/dist-packages
    six: 1.14.0 from /usr/lib/python3/dist-packages
  Mopidy: 3.0.2 from /usr/lib/python3/dist-packages
  setuptools: 45.2.0 from /usr/lib/python3/dist-packages
Mopidy-Scrobbler: 2.0.0 from /usr/lib/python3/dist-packages
Mopidy-Iris: 3.49.0 from /usr/local/lib/python3.8/dist-packages
  setuptools: 45.2.0 from /usr/lib/python3/dist-packages
  Pykka: 2.0.2 from /usr/lib/python3/dist-packages
  Mopidy: 3.0.2 from /usr/lib/python3/dist-packages
Mopidy-Spotify: 4.0.1 from /usr/lib/python3/dist-packages
Mopidy-MPD: 3.0.0 from /usr/lib/python3/dist-packages
Mopidy-Local: 3.1.1 from /usr/lib/python3/dist-packages
GStreamer: 1.16.2.0 from /usr/lib/python3/dist-packages/gi
  Detailed information:
    Python wrapper: python-gi 3.36.0
    Relevant elements:
      Found:
        uridecodebin
        souphttpsrc
        appsrc
        alsasink
        osssink
        oss4sink
        pulsesink
        id3demux
        id3v2mux
        lamemp3enc
        mpegaudioparse
        mpg123audiodec
        vorbisdec
        vorbisenc
        vorbisparse
        oggdemux
        oggmux
        oggparse
        flacdec
        flacparse
        shout2send
      Not found:
        flump3dec
        mad
sudo mopidyctl config
Running "/usr/bin/mopidy --config /usr/share/mopidy/conf.d:/etc/mopidy/mopidy.conf config" as user mopidy
[core]
cache_dir = /var/cache/mopidy
config_dir = /etc/mopidy
data_dir = /var/lib/mopidy
max_tracklist_length = 10000
restore_state = false

[logging]
verbosity = 0
format = %(levelname)-8s [%(threadName)s] %(name)s %(message)s
color = false
config_file =

[audio]
mixer = software
mixer_volume = 100
output = lamemp3enc ! shout2send async=true mount=/mopidy ip=127.0.0.1 port=8000 password=hackme
buffer_time =

[proxy]
scheme =
hostname =
port =
username =
password =

[musicbox_webclient]
enabled = true
musicbox = false
websocket_host =
websocket_port =
on_track_click = PLAY_ALL

[mopify]
enabled = true
debug = false

[iris]
enabled = true
country = NZ
locale = en_NZ
spotify_authorization_url = https://jamesbarnsley.co.nz/iris/auth_spotify.php
lastfm_authorization_url = https://jamesbarnsley.co.nz/iris/auth_lastfm.php
genius_authorization_url = https://jamesbarnsley.co.nz/iris/auth_genius.php
data_dir = $XDG_DATA_DIR/iris

[file]
enabled = true
media_dirs =
  $XDG_MUSIC_DIR|Music
  ~/|Home
excluded_file_extensions =
  .directory
  .html
  .jpeg
  .jpg
  .log
  .nfo
  .pdf
  .png
  .txt
  .zip
show_dotfiles = false
follow_symlinks = false
metadata_timeout = 1000

[http]
enabled = true
hostname = 0.0.0.0
port = 6680
zeroconf = Mopidy HTTP server on $hostname
allowed_origins =
csrf_protection = true
default_app = mopidy

[m3u]
enabled = true
base_dir =
default_encoding = latin-1
default_extension = .m3u8
playlists_dir =

[softwaremixer]
enabled = true

[stream]
enabled = true
protocols =
  http
  https
  mms
  rtmp
  rtmps
  rtsp
metadata_blacklist =
timeout = 5000

[tunein]
enabled = true
timeout = 5000
filter =

[spotify]
enabled = true
username = REDACTED
password = REDACTED
client_id = REDACTED
client_secret = REDACTED
bitrate = 160
volume_normalization = true
private_session = false
timeout = 10
allow_cache = true
allow_network = true
allow_playlists = true
search_album_count = 20
search_artist_count = 10
search_track_count = 50
toplist_countries =

[scrobbler]
enabled = true
username = gravyflex
password = ********

[mpd]
enabled = true
hostname = 0.0.0.0
port = 6600
password = ********
max_connections = 20
connection_timeout = 60
zeroconf = Mopidy MPD server on $hostname
command_blacklist =
  listall
  listallinfo
default_playlist_scheme = m3u

[local]
enabled = true
media_dir = /var/music
scan_timeout = 1000
scan_flush_threshold = 100
scan_follow_symlinks = false
included_file_extensions =
excluded_file_extensions =
  .cue
  .directory
  .html
  .jpeg
  .jpg
  .log
  .nfo
  .pdf
  .png
  .txt
  .zip
directories =
  Albums                  local:directory?type=album
  Artists                 local:directory?type=artist
  Composers               local:directory?type=artist&role=composer
  Genres                  local:directory?type=genre
  Performers              local:directory?type=artist&role=performer
  Release Years           local:directory?type=date&format=%25Y
  Tracks                  local:directory?type=track
  Last Week's Updates     local:directory?max-age=604800
  Last Month's Updates    local:directory?max-age=2592000
timeout = 10
use_artist_sortname = false
album_art_files =
  *.jpg
  *.jpeg
  *.png

I am able to play audio successfully via snapcast with the following Audio settings

output = audioconvert ! audio/x-raw,rate=48000,channels=2,format=S16LE ! wavenc ! filesink location=/tmp/snapfifo