Can't start an update of Hass.io Core installation to a newest version from Supervisor panel nor restarting server from Configuration panel

Hi Home Assistant Community users,
Can’t find my solution myself in the forum and I’m despite.
Be gently with me because I’m totally new in Home Assistant and would like to know from your advice how can I solve my problem described below :

  • I cannot start an update of Home Assistant Core installation to a newest version from Supervisor panel nor restarting server from Configuration panel.
  • The message on Log Provider Supervisor is always :
    ERROR (MainThread) [supervisor.utils] Can’t execute update while a task is in progress

Hass.io on Docker 19.03.13 installed on an INTEL NUC with operating system Ubuntu 20.04.1 LTS

System Health

arch x86_64
chassis desktop
dev false
docker true
docker_version 19.03.13
hassio true
host_os Ubuntu 20.04.1 LTS
installation_type Home Assistant Supervised
os_name Linux
os_version 5.4.0-54-generic
python_version 3.8.6
supervisor 2020.11.0
timezone Europe/Zurich
version 0.117.6
virtualenv false

Lovelace

dashboards 1
mode auto-gen
resources 0
20-11-28 20:18:12 ERROR (MainThread) [supervisor.core] Detected unsupported OS: Ubuntu 20.04.1 LTS
20-11-28 20:18:12 INFO (MainThread) [__main__] Running Supervisor
20-11-28 20:18:12 WARNING (MainThread) [supervisor.core] System running in a unsupported environment!
20-11-28 20:18:12 INFO (MainThread) [supervisor.addons] Phase 'AddonStartup.INITIALIZE' starting 0 add-ons
20-11-28 20:18:12 INFO (MainThread) [supervisor.addons] Phase 'AddonStartup.SYSTEM' starting 1 add-ons
20-11-28 20:18:12 INFO (SyncWorker_3) [supervisor.docker.interface] Cleaning addon_core_mosquitto application
20-11-28 20:18:13 INFO (SyncWorker_3) [supervisor.docker.addon] Starting Docker add-on homeassistant/amd64-addon-mosquitto with version 5.1
20-11-28 20:18:14 INFO (MainThread) [supervisor.services.modules.mqtt] Set core_mosquitto as service provider for mqtt
20-11-28 20:18:18 INFO (MainThread) [supervisor.addons] Phase 'AddonStartup.SERVICES' starting 2 add-ons
20-11-28 20:18:18 INFO (SyncWorker_1) [supervisor.docker.interface] Cleaning addon_core_zwave application
20-11-28 20:18:19 INFO (SyncWorker_1) [supervisor.docker.addon] Starting Docker add-on homeassistant/amd64-addon-zwave with version 0.5.2
20-11-28 20:18:19 INFO (SyncWorker_3) [supervisor.docker.interface] Cleaning addon_core_deconz application
20-11-28 20:18:19 INFO (SyncWorker_3) [supervisor.docker.addon] Starting Docker add-on homeassistant/amd64-addon-deconz with version 6.5.0
20-11-28 20:18:24 INFO (SyncWorker_3) [supervisor.docker.interface] Starting homeassistant
20-11-28 20:18:25 INFO (MainThread) [supervisor.homeassistant.core] Wait until Home Assistant is ready
20-11-28 20:47:31 INFO (SyncWorker_1) [supervisor.docker.addon] Starting Docker add-on homeassistant/amd64-addon-configurator with version 5.2.0
20-11-28 21:09:48 ERROR (MainThread) [supervisor.utils] Can't execute update while a task is in progress

Nobody is helping me…
I’m not understanding why Home Assistant is waiting.

INFO (MainThread) [supervisor.homeassistant.core] Wait until Home Assistant is ready

Also I can’t access to Hass.io from another internal nor external computer using the http://my.local.IP:8123
Thanks for your help.