unable to instlal repo

I am unable to install the webmin repo onto a newly minted ubuntu 20.04 LTS machine:

root@web2:~# cd /root root@web2:~# wget https://download.webmin.com/jcameron-key.asc --2020-12-09 13:47:21-- https://download.webmin.com/jcameron-key.asc Resolving download.webmin.com (download.webmin.com)... 104.207.151.13, 108.60.199.109 Connecting to download.webmin.com (download.webmin.com)|104.207.151.13|:443... connected. ERROR: cannot verify download.webmin.com's certificate, issued by ‘CN=Let's Encrypt Authority X3,O=Let's Encrypt,C=US’: Unable to locally verify the issuer's authority. To connect to download.webmin.com insecurely, use --no-check-certificate'. root@web2:~# apt-key add jcameron-key.asc gpg: can't open 'jcameron-key.asc': No such file or directory root@web2:~# wget https://download.webmin.com/jcameron-key.asc --2020-12-09 13:48:05-- https://download.webmin.com/jcameron-key.asc Resolving download.webmin.com (download.webmin.com)... 104.207.151.13, 108.60.199.109 Connecting to download.webmin.com (download.webmin.com)|104.207.151.13|:443... connected. ERROR: cannot verify download.webmin.com's certificate, issued by ‘CN=Let's Encrypt Authority X3,O=Let's Encrypt,C=US’: Unable to locally verify the issuer's authority. To connect to download.webmin.com insecurely, use--no-check-certificate'. root@web2:~# wget https://download.webmin.com/jcameron-key.asc --no-check-certificate --2020-12-09 13:48:29-- https://download.webmin.com/jcameron-key.asc Resolving download.webmin.com (download.webmin.com)... 104.207.151.13, 108.60.199.109 Connecting to download.webmin.com (download.webmin.com)|104.207.151.13|:443... connected. WARNING: cannot verify download.webmin.com's certificate, issued by ‘CN=Let's Encrypt Authority X3,O=Let's Encrypt,C=US’: Unable to locally verify the issuer's authority. HTTP request sent, awaiting response... 200 OK Length: 1320 (1.3K) [text/plain] Saving to: ‘jcameron-key.asc’

jcameron-key.asc 100%[=========================================================>] 1.29K --.-KB/s in 0s

2020-12-09 13:48:30 (45.4 MB/s) - ‘jcameron-key.asc’ saved [1320/1320]

root@web2:~# apt-key add jcameron-key.asc OK root@web2:~# apt update Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease Hit:3 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease Hit:4 http://us.archive.ubuntu.com/ubuntu focal-security InRelease Ign:5 https://download.webmin.com/download/repository sarge InRelease Err:6 https://download.webmin.com/download/repository sarge Release Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 104.207.151.13 443] Reading package lists... Done E: The repository 'https://download.webmin.com/download/repository sarge 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. root@web2:~#