7.2 to 7.3 problems "does not have a Release file."

Ubuntu 16.04.6 LTS

Trying to update elasticsearch from 7.2 to 7.3 ...

W: The repository 'https://artifacts.elastic.co/packages/7.x/apt stable Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch https://artifacts.elastic.co/packages/7.x/apt/dists/stable/main/binary-amd64/Packages  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
E: Some index files failed to download. They have been ignored, or old ones used instead.

Keeps giving me this error... even if I remove the elastic-7.x.list from /etc/apt/sources.list.d and re-add echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
... I get the same problem.

This is a 2 node cluster and the other node updated without a problem and the /etc/apt/sources.list.d looks exactly the same in both...

Any suggestions?