Webmin is broken on ubuntu 20.04 trying to upgrade authentic theme -- unable to access interface - [ERROR] No repos available for this OS. Are you running unstable/testing?

this could also happen after upgrade to ubuntu 20.04 but quite unlikely

Your next move should be

We can go to the official

https://www.webmin.com/download.html">Webmin download page

and search for the package we need, but in this case we already know the URL where we can find the package. So we will use wget to download the .deb package to a suitable folder:

# wget http://prdownloads.sourceforge.net/webadmin/webmin_1.941_all.deb

What does stands out of the crowd here, and you will notice if you check the download site, that there is a single package for Debian, Ubuntu, and all other derivative distros – no package by distribution, and no package by release of that given distribution. A single package for all, and this single package works out of the box. Refreshingly simple.


Next step....

Installing Webmin from .deb package

# sudo dpkg --install webmin_1.941_all.deb


Installation will provide output. At the end of it, you may find a notice regarding the URL we’ll need to access Webmin:

Webmin install complete. You can now login to https://domain.com:10000/
as root with your root password, or as any user who can use sudo
to run commands as root.