我正在运行这些命令以在Ubuntu 20.04.4 LTS上安装pgAdmin

# 

# Setup the repository

# 

# Install the public key for the repository (if not done previously):

sudo curl https://www.pgadmin.org/static/packages_pgadmin_org.pub | sudo apt-key add

# Create the repository configuration file:

sudo sh -c 'echo "deb https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/$(lsb_release -cs) pgadmin4 main" > /etc/apt/sources.list.d/pgadmin4.list && apt update'

# 

# Install pgAdmin

# 

# Install for both desktop and web modes:

sudo apt install pgadmin4

# Install for desktop mode only:

sudo apt install pgadmin4-desktop

# Install for web mode only:

sudo apt install pgadmin4-web 

# Configure the webserver, if you installed pgadmin4-web:

sudo /usr/pgadmin4/bin/setup-web.sh

https://www.pgadmin.org/download/pgadmin-4-apt/
一切都进行得很顺利，直到我发出这个命令：
sudo /usr/pgadmin4/bin/setup-web.sh
它会产生以下输出：

Creating configuration database...
pgAdmin 4 - Application Initialisation
======================================

Creating storage and log directories...
We can now configure the Apache Web server for you. This involves enabling the wsgi module and configuring the pgAdmin 4 application to mount at /pgadmin4. Do you wish to continue (y/n)? y
ERROR: Conf pgadmin4 does not exist!

我错过了什么？