E: The repository 'https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/focal pgadmin4 Release' does not have a Release file.

[webb24h]

I follow this very well crafted tutorial to install pgadmin4-web on Stackoverflow

But When I get to step 5, I see this error in the console :

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'
Hit:1 http://ca.archive.ubuntu.com/ubuntu focal InRelease
Get:2 http://ca.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]     
Get:3 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]      
Get:4 http://ca.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]   
Ign:5 https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/focal pgadmin4 InRelease
Err:6 https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/focal pgadmin4 Release
  Certificate verification failed: The certificate is NOT trusted. The certificate chain uses expired certificate.  Could not handshake: Error in the certificate verification. [IP: 217.196.149.55 443]
Reading package lists... Done                        
E: The repository 'https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/focal pgadmin4 Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I'm on Ubuntu 20.04 LTS. What is the solution?

[webb24h]

We can mark this as solved. I found the solution right here : https://askubuntu.com/questions/1095266/apt-get-update-failed-because-certificate-verification-failed-because-handshake