Package 'libappindicator0.1-cil' has no installation candidate

I cannot even get off the ground here to install duplicati. Everything is up to date on my ubuntu 20.04 server and I’m not sure where to go from here. BTW I deleted the H infront of HTTPS so I could post this.

root@sr1:~# sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
Executing: /tmp/apt-key-gpghome.fcABPCRMo1/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
gpg: key A6A19B38D3D831EF: “Xamarin Public Jenkins (auto-signing) releng@xamarin.com” not changed
gpg: Total number processed: 1
gpg: unchanged: 1

root@sr1:~# echo “deb ttps://download.mono-project.com/repo/ubuntu stable-focal main” | sudo tee /etc/apt/sources.list.d/mono-official-stable.list
deb ttps://download.mono-project.com/repo/ubuntu stable-focal main

root@sr1:~# sudo apt update
Hit:1 ttp://ppa.launchpad.net/ondrej/apache2/ubuntu focal InRelease
Hit:2 ttp://ppa.launchpad.net/ondrej/php/ubuntu focal InRelease
Hit:3 ttps://apt.hestiacp.com focal InRelease
Hit:4 ttps://mirror.mva-n.net/mariadb/repo/10.5/ubuntu focal InRelease
Hit:5 ttps://nginx.org/packages/mainline/ubuntu focal InRelease
Hit:6 ttps://download.mono-project.com/repo/ubuntu stable-focal InRelease
Reading package lists… Done
Building dependency tree
Reading state information… Done
All packages are up to date.

root@sr1:~# sudo apt install mono-devel gtk-sharp2 libappindicator0.1-cil libmono-2.0-1
Reading package lists… Done
Building dependency tree
Reading state information… Done
Package libappindicator0.1-cil is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package ‘libappindicator0.1-cil’ has no installation candidate

Anyone getting the same error? Is Duplicati no longer providing support for their application?

Hello, I can set up an Ubuntu 20.04 vm for testing. In the meantime try installing just mono:

$ sudo apt install mono-devel

(Leave off those other things for the moment.)

Once that is installed, proceed to installing the duplicati deb package.

“Unable to locate package” while trying to install packages with APT might be worth looking at.
Make sure you have universe. If no GUI, maybe grep universe /etc/apt/sources.list

https://packages.ubuntu.com/search?suite=focal&searchon=names&keywords=libappindicator0.1-cil

On the other hand, if you don’t have universe, how did you get the below, or did you get this?

https://packages.ubuntu.com/search?suite=focal&section=all&arch=any&keywords=gtk-sharp2&searchon=names

Maybe one step at a time is a good strategy. I’m not an apt expert, so can’t give deep advice here.

Thank you actions taken within Ubuntu – Package Search Results -- libappindicator0.1-cil resolved the issue.