Telegram Desktop no Linux Mint (Erro)

https://www.vivaolinux.com.br/dica/Telegram-Desktop-no-Linux-Mint-e-Ubuntu ( Li o tutorial) porém apareceu este erro : "sudo add-apt-repository ppa:atareao/telegram

Você está prestes a adicionar o seguinte PPA para o seu sistema:
Telegram Desktop for Linux. Both 32 and 64 bit.
Mais informações: https://launchpad.net/~atareao/+archive/ubuntu/telegram
Pressione [ENTER] para continuar ou ctrl-c para cancelar a adição
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.7q5HxcY7Ls --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36FD5529
gpg: requesting key 36FD5529 from hkp server keyserver.ubuntu.com
gpg: key 36FD5529: "Launchpad PPA for atareao" not changed
gpg: Total number processed: 1"

Como devo proceder para resolver?

sudo apt-get update
Ign http://br.archive.ubuntu.com utopic InRelease
Ign http://extras.ubuntu.com utopic InRelease
Ign http://ppa.launchpad.net utopic InRelease
Ign http://br.archive.ubuntu.com utopic-updates InRelease
Ign http://security.ubuntu.com utopic-security InRelease
Obter:1 http://extras.ubuntu.com utopic Release.gpg [72 B]
Ign http://br.archive.ubuntu.com utopic-backports InRelease
Ign http://ppa.launchpad.net utopic InRelease
Ign http://br.archive.ubuntu.com utopic Release.gpg
Ign http://security.ubuntu.com utopic-security Release.gpg
Obter:2 http://extras.ubuntu.com utopic Release [14,0 kB]
Ign http://ppa.launchpad.net utopic InRelease
Ign http://br.archive.ubuntu.com utopic-updates Release.gpg
Ign http://security.ubuntu.com utopic-security Release
Ign http://br.archive.ubuntu.com utopic-backports Release.gpg
Ign http://ppa.launchpad.net utopic InRelease
Ign http://security.ubuntu.com utopic-security/main Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic Release
Obter:3 http://ppa.launchpad.net utopic InRelease [15,5 kB]
Ign http://br.archive.ubuntu.com utopic-updates Release
Ign http://security.ubuntu.com utopic-security/restricted Sources/DiffIndex
Obter:4 http://ppa.launchpad.net utopic InRelease [15,5 kB]
Ign http://br.archive.ubuntu.com utopic-backports Release
Ign http://security.ubuntu.com utopic-security/universe Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic/main Sources/DiffIndex
Ign http://security.ubuntu.com utopic-security/multiverse Sources/DiffIndex
Obter:5 http://ppa.launchpad.net utopic InRelease [15,5 kB]
Ign http://br.archive.ubuntu.com utopic/restricted Sources/DiffIndex
Ign http://security.ubuntu.com utopic-security/main i386 Packages/DiffIndex
Obter:6 http://ppa.launchpad.net utopic Release.gpg [316 B]
Ign http://br.archive.ubuntu.com utopic/universe Sources/DiffIndex
Obter:7 http://extras.ubuntu.com utopic/main Sources [14 B]
Ign http://br.archive.ubuntu.com utopic/multiverse Sources/DiffIndex
Ign http://security.ubuntu.com utopic-security/restricted i386 Packages/DiffIndex
Obter:8 http://ppa.launchpad.net utopic Release.gpg [316 B]
Obter:9 http://extras.ubuntu.com utopic/main i386 Packages [14 B]
Ign http://br.archive.ubuntu.com utopic/main i386 Packages/DiffIndex
Ign http://security.ubuntu.com utopic-security/universe i386 Packages/DiffIndex
Ign http://ppa.launchpad.net utopic Release.gpg
Ign http://br.archive.ubuntu.com utopic/restricted i386 Packages/DiffIndex
Ign http://security.ubuntu.com utopic-security/multiverse i386 Packages/DiffIndex
Obter:10 http://ppa.launchpad.net utopic Release.gpg [316 B]
Ign http://br.archive.ubuntu.com utopic/universe i386 Packages/DiffIndex
Obter:11 http://ppa.launchpad.net utopic/main i386 Packages [15,3 kB]
Ign http://br.archive.ubuntu.com utopic/multiverse i386 Packages/DiffIndex
Obter:12 http://ppa.launchpad.net utopic/main Translation-en [7.783 B]
Ign http://extras.ubuntu.com utopic/main Translation-pt_BR
Obter:13 http://ppa.launchpad.net utopic Release [15,1 kB]
Ign http://extras.ubuntu.com utopic/main Translation-pt
Obter:14 http://ppa.launchpad.net utopic Release [15,1 kB]
Ign http://extras.ubuntu.com utopic/main Translation-en
Ign http://ppa.launchpad.net utopic Release
Obter:15 http://ppa.launchpad.net utopic Release [15,1 kB]
Obter:16 http://ppa.launchpad.net utopic/main i386 Packages [14 B]
Ign http://br.archive.ubuntu.com utopic-updates/main Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic-updates/restricted Sources/DiffIndex
Obter:17 http://ppa.launchpad.net utopic/main Translation-en [14 B]
Ign http://br.archive.ubuntu.com utopic-updates/universe Sources/DiffIndex
Obter:18 http://ppa.launchpad.net utopic/main i386 Packages [14 B]
Ign http://br.archive.ubuntu.com utopic-updates/multiverse Sources/DiffIndex
Obter:19 http://ppa.launchpad.net utopic/main Translation-en [14 B]
Ign http://br.archive.ubuntu.com utopic-updates/main i386 Packages/DiffIndex
Ign http://br.archive.ubuntu.com utopic-updates/restricted i386 Packages/DiffIndex
Obter:20 http://ppa.launchpad.net utopic/main i386 Packages [14 B]
Ign http://br.archive.ubuntu.com utopic-updates/universe i386 Packages/DiffIndex
Obter:21 http://ppa.launchpad.net utopic/main Translation-en [14 B]
Ign http://br.archive.ubuntu.com utopic-updates/multiverse i386 Packages/DiffIndex
Obter:22 http://ppa.launchpad.net utopic/main i386 Packages [14 B]
Obter:23 http://ppa.launchpad.net utopic/main Translation-en [14 B]
Ign http://br.archive.ubuntu.com utopic-backports/main Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic-backports/restricted Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic-backports/universe Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic-backports/multiverse Sources/DiffIndex
Ign http://br.archive.ubuntu.com utopic-backports/main i386 Packages/DiffIndex
Obter:24 http://ppa.launchpad.net utopic/main i386 Packages [4.517 B]
Ign http://br.archive.ubuntu.com utopic-backports/restricted i386 Packages/DiffIndex
Obter:25 http://ppa.launchpad.net utopic/main Translation-en [3.374 B]
Ign http://br.archive.ubuntu.com utopic-backports/universe i386 Packages/DiffIndex
Ign http://br.archive.ubuntu.com utopic-backports/multiverse i386 Packages/DiffIndex
Err http://ppa.launchpad.net utopic/main i386 Packages
404 Not Found
Ign http://ppa.launchpad.net utopic/main Translation-pt_BR
Ign http://ppa.launchpad.net utopic/main Translation-pt
Ign http://ppa.launchpad.net utopic/main Translation-en
Ign http://security.ubuntu.com utopic-security/main Translation-pt_BR
Ign http://security.ubuntu.com utopic-security/main Translation-pt
Ign http://security.ubuntu.com utopic-security/main Translation-en
Ign http://security.ubuntu.com utopic-security/multiverse Translation-pt_BR
Ign http://security.ubuntu.com utopic-security/multiverse Translation-pt
Ign http://security.ubuntu.com utopic-security/multiverse Translation-en
Ign http://security.ubuntu.com utopic-security/restricted Translation-pt_BR
Ign http://security.ubuntu.com utopic-security/restricted Translation-pt
Ign http://security.ubuntu.com utopic-security/restricted Translation-en
Ign http://security.ubuntu.com utopic-security/universe Translation-pt_BR
Ign http://security.ubuntu.com utopic-security/universe Translation-pt
Ign http://security.ubuntu.com utopic-security/universe Translation-en
Err http://security.ubuntu.com utopic-security/main Sources
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/restricted Sources
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/universe Sources
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/multiverse Sources
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/main i386 Packages
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/restricted i386 Packages
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/universe i386 Packages
404 Not Found [IP: 91.189.88.152 80]
Err http://security.ubuntu.com utopic-security/multiverse i386 Packages
404 Not Found [IP: 91.189.88.152 80]
100% [Aguardando por cabeçalhos]sudo apt-get install telegram
Ign http://br.archive.ubuntu.com utopic/main Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic/main Translation-pt
Ign http://br.archive.ubuntu.com utopic/main Translation-en
Ign http://br.archive.ubuntu.com utopic/multiverse Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic/multiverse Translation-pt
Ign http://br.archive.ubuntu.com utopic/multiverse Translation-en
Ign http://br.archive.ubuntu.com utopic/restricted Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic/restricted Translation-pt
Ign http://br.archive.ubuntu.com utopic/restricted Translation-en
Ign http://br.archive.ubuntu.com utopic/universe Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic/universe Translation-pt
Ign http://br.archive.ubuntu.com utopic/universe Translation-en
Ign http://br.archive.ubuntu.com utopic-updates/main Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-updates/main Translation-pt
Ign http://br.archive.ubuntu.com utopic-updates/main Translation-en
Ign http://br.archive.ubuntu.com utopic-updates/multiverse Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-updates/multiverse Translation-pt
Ign http://br.archive.ubuntu.com utopic-updates/multiverse Translation-en
Ign http://br.archive.ubuntu.com utopic-updates/restricted Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-updates/restricted Translation-pt
Ign http://br.archive.ubuntu.com utopic-updates/restricted Translation-en
Ign http://br.archive.ubuntu.com utopic-updates/universe Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-updates/universe Translation-pt
Ign http://br.archive.ubuntu.com utopic-updates/universe Translation-en
Ign http://br.archive.ubuntu.com utopic-backports/main Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-backports/main Translation-pt
Ign http://br.archive.ubuntu.com utopic-backports/main Translation-en
Ign http://br.archive.ubuntu.com utopic-backports/multiverse Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-backports/multiverse Translation-pt
Ign http://br.archive.ubuntu.com utopic-backports/multiverse Translation-en
Ign http://br.archive.ubuntu.com utopic-backports/restricted Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-backports/restricted Translation-pt
Ign http://br.archive.ubuntu.com utopic-backports/restricted Translation-en
Ign http://br.archive.ubuntu.com utopic-backports/universe Translation-pt_BR
Ign http://br.archive.ubuntu.com utopic-backports/universe Translation-pt
Ign http://br.archive.ubuntu.com utopic-backports/universe Translation-en
Err http://br.archive.ubuntu.com utopic/main Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/restricted Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/universe Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/multiverse Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/main i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/restricted i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/universe i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic/multiverse i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/main Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/restricted Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/universe Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/multiverse Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/main i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/restricted i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/universe i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-updates/multiverse i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/main Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/restricted Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/universe Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/multiverse Sources
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/main i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/restricted i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/universe i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Err http://br.archive.ubuntu.com utopic-backports/multiverse i386 Packages
404 Not Found [IP: 200.236.31.4 80]
Baixados 138 kB em 6min 55s (331 B/s)
W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/main/source/Sources 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/restricted/source/Sources 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/universe/source/Sources 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/main/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/multiverse/source/Sources 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/restricted/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/main/binary-i386/Packages 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/universe/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/multiverse/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/restricted/binary-i386/Packages 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/main/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/universe/binary-i386/Packages 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/restricted/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://security.ubuntu.com/ubuntu/dists/utopic-security/multiverse/binary-i386/Packages 404 Not Found [IP: 91.189.88.152 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/universe/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic/multiverse/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://ppa.launchpad.net/format-junkie-team/release/ubuntu/dists/utopic/main/binary-i386/Packages 404 Not Found

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/main/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/restricted/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/universe/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/multiverse/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/main/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/restricted/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/universe/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-updates/multiverse/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/main/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/restricted/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/universe/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/multiverse/source/Sources 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/main/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/restricted/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/universe/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

W: Falhou ao buscar http://br.archive.ubuntu.com/ubuntu/dists/utopic-backports/multiverse/binary-i386/Packages 404 Not Found [IP: 200.236.31.4 80]

E: Falhou o download de alguns ficheiros de índice. Foram ignorados ou os antigos foram usados em seu lugar.
System-Product-Name:~$ sudo apt-get install telegram
Lendo listas de pacotes... Pronto
Construindo árvore de dependências
Lendo informação de estado... Pronto
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Quais os passos devo dar para resolver este erro?

2 coisas:
vc está usando ubuntu vencido. Instale uma versão mais recente; 14.04 ou 16.04.
Telegram NÃO precisa instalar! é só baixar a pasta e clicar no executável.
leia isto:
http://ubuntuhandbook.org/index.php/2015/07/ubuntu-14-10-utopic-end-of-life/



-----------------------------------------------------------------------------------------------
Não importa a distro que você usa, o que importa é o que você faz com ela.