Any idea why am i getting such error? and, how could I fix it?
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9
Executing: /tmp/apt-key-gpghome.QThU5VY9Yd/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9 gpg: key 51716619E084DAB9: "Michael Rutter <firstname.lastname@example.org>" not changed gpg: Total number processed: 1 gpg: unchanged: 1
sudo add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/'
Ign:1 http://ppa.launchpad.net/marutter/rrutter/ubuntu focal InRelease Hit:2 https://desktop-download.mendeley.com/download/apt stable InRelease Hit:3 https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/ InRelease Err:4 http://ppa.launchpad.net/marutter/rrutter/ubuntu focal Release 404 Not Found [IP: 184.108.40.206 80] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/marutter/rrutter/ubuntu focal 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.
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