I updated my OS to Ubuntu 19.04. I had been using pgadmin4 on Ubuntu 18.10 and it worked without problems, but now that I have updated I get this error:

the application server could not be contacted

I tried uninstalling pgadmin4 and reinstalling but without improvement.

I also reactivated the postgresql repository because when updating to Ubuntu 19.04 I deactivated some repositories.

  • is your postgres server running? – JayEye Apr 21 '19 at 19:37
  • HI @Kenetch did something worked for you? I am still having this issue. – Andrew James Ramirez May 18 '20 at 11:04
  • Hi @AndrewJamesRamirez. the desktop application does not work, but I installed the version of apache2 and that works well for me, currently I use everything with docker, but at the time I use it with apache. – KenetCh May 18 '20 at 13:24

Try following the advice in this article: How to Install and Configure pgAdmin4 on Ubuntu 18.04 & 16.04

Remove the previous installation

sudo apt-get remove pgadmin4

and reinstall

sudo apt-get install wget ca-certificates
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" >> /etc/apt/sources.list.d/pgdg.list'
sudo apt-get update
sudo apt-get install pgadmin4 pgadmin4-apache2

for me it worked.


On Ubuntu 20.04, If,

sudo python3 /usr/share/pgadmin4/web/pgAdmin4.py

gives an error,

FileNotFoundError: [Errno 2] No such file or directory: '/var/cache/pgadmin/sessions'

Simply create the missing file path as,

sudo mkdir -p /var/cache/pgadmin/sessions

and rerun,

sudo python3 /usr/share/pgadmin4/web/pgAdmin4.py

For output as below -

$ sudo python3 /usr/share/pgadmin4/web/pgAdmin4.py
NOTE: Configuring authentication for SERVER mode.
Enter the email address and password to use for the initial pgAdmin user account:
Email address: what_ever@email_u_like.com
Retype password:

pgAdmin 4 - Application Initialisation

Starting pgAdmin 4. Please navigate to ****** in your browser.

 * Serving Flask app "pgadmin" (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off

This would present the pgAdmin4 login window in your browser.


Just try from terminal :

$ pgadmin4

It will result just like this :

Python path:  "/usr/lib/python3/dist-packages" 
Python Home:  ""
Webapp path:  "/usr/share/pgadmin4/web/pgAdmin4.py"

If it doesn't work ,copy webapp path and You can start it manually:

$ sudo python3 /usr/share/pgadmin4/web/pgAdmin4.py

I had to do

sudo mkdir /var/cache/pgadmin/

before starting pgadmin4.


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