Certificate verification failed for pgadmin4 desktop installation in linux

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@pgadmin.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?