Problem with gnome-software under Ubuntu 18.04.4 LTS (Bionic Beaver) because of Proxy Authentication Required

I have a problem with the application gnome-software under Ubuntu 18.04.4 LTS (Bionic Beaver) in my virtual machine of Oracle VM VirtualBox.
I am unable to access the applications in the gnome-software software library due to the proxy problem.

I have these 3 error messages:

1. 08: 55: 54: 0026 Gs failed to call gs_plugin_refresh on shell-extensions: [* / * / * / source / shell-extensions / *] failed to download https://extensions.gnome.org//static/extensions .json: Proxy Authentication Required
2. same problem for fwupd: Proxy Authentication Required
3. same problem for odrs: Proxy Authentication Required

However, I have followed the explanations on the internet several other links.

I have defined my proxy:

1. in my ".bashrc" file which contains 4 exports:
   export HTTPS_PROXY=’http://userName:[email protected]:myPortNumber’
   similar to : export HTTP_PROXY=’…’
   similar to export https_proxy=’…’
   similar to export http_proxy=’…’
2. In the Preferences under the Network tab, I defined authentication for my proxies,

3. and also in /etc/apt/apt.conf.d/proxy.conf with
   Acquire::http::Proxy "http://userName:[email protected]:myPortNumber";
   Acquire::https::Proxy "http://userName:[email protected]:myPortNumber";

My password contains a special character $, I replaced it with the equivalent of hexadecimal code which is "%24".

After running the commands below:

sudo apt update -y && sudo apt upgrade -y
sudo apt full-upgrade
sudo apt install meld
sudo apt install git

it works without problems!

My Firefox application works without problems!

I reinstalled Ubuntu 2 times but I still have these 3 error messages from the gnome-software application:

1. killall gnome-software
   gnome-software
2. sudo apt-get install -f gnome-software
3. sudo apt install --reinstall gnome-software
4. sudo apt-get remove gnome-software
sudo apt-get install -f gnome-software

The online order of gnome-software indicates:

Could you help me to understand if this is a bug or how to fix it?

I can’t find the answers on the internet. I have tried all of the methods listed on the internet.