The PPA https://launchpad.net/~marutter/+archive/ubuntu/c2d4u has not been updated for Ubuntu 20.04. You should remove that PPA and find an alternative source for these or similar packages. After removing the PPA updating should proceed without error.
This is not a bug but simply an error message telling you that your system is trying to get information about packages for Ubuntu 20.04 that do not exist. ** Tags added: focal ** Changed in: ubuntu Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1898806 Title: I get an error when I try to install R in Ubuntu 20.04.1 LTS How can I fix it? To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1898806/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs