Certificate verification failed for pgadmin4 desktop installation in linux

Hi, I'm trying to install pg4admin desktop by following instructions on:
https://www.pgadmin.org/download/pgadmin-4-apt/

I'm on a Linux Mint 20.1 ulyssa system, equivalent ubuntu codename is
"focal". So, I have to put "focal" for release name.

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

Verified that its there by apt-key list:
pub rsa4096 2018-08-14 [SC]
E869 7E2E EF76 C02D 3A63 3277 8881 B2A8 2109 76F2
uid [ unknown] Package Manager (Package Signing Key) <
packages(at)pgadmin(dot)org>
sub rsa4096 2018-08-14 [E]

Added the repository (putting "focal" release name in place of
$(lsb_release -cs):

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

But this is what I get:

The following signatures couldn't be verified because the public key is
not available: NO_PUBKEY 46B5721DBBD2996A
Err:10 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: 87.238.57.227 443]

I'm going to
https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/focal/dists/pgadmin4/main/binary-amd64/
and just downloading the .debs and doing install for now.
But guessing somebody from the maintainers might need to renew the
certificate or something?

--
Cheers,
Nikhil VJ
https://nikhilvj.co.in