Installation error of jitsi

I am installing jitsi in client-server using an SSH connection

I have performed following steps successfully

  1. echo ‘deb https://download.jitsi.org stable/’ >> /etc/apt/sources.list.d/jitsi-stable.list
  2. wget -qO - https://download.jitsi.org/jitsi-key.gpg.key | sudo apt-key add -
    3)apt-get install apt-transport-https

But when I do apt-get update we are getting the following error

Hit:1 http://packages.prosody.im/debian xenial InRelease
Hit:2 http://security.ubuntu.com/ubuntu xenial-security InRelease
Ign:3 https://download.jitsi.org stable/ InRelease
Hit:4 http://sa.archive.ubuntu.com/ubuntu xenial InRelease
Hit:5 http://sa.archive.ubuntu.com/ubuntu xenial-updates InRelease
Ign:6 https://download.jitsi.org stable/ Release
Hit:7 http://sa.archive.ubuntu.com/ubuntu xenial-backports InRelease
Ign:8 https://download.jitsi.org stable/ Packages
Ign:9 https://download.jitsi.org stable/ Translation-en_US
Ign:10 https://download.jitsi.org stable/ Translation-en
Ign:8 https://download.jitsi.org stable/ Packages
Ign:9 https://download.jitsi.org stable/ Translation-en_US
Ign:10 https://download.jitsi.org stable/ Translation-en
Ign:8 https://download.jitsi.org stable/ Packages
Ign:9 https://download.jitsi.org stable/ Translation-en_US
Ign:10 https://download.jitsi.org stable/ Translation-en
Ign:8 https://download.jitsi.org stable/ Packages
Ign:9 https://download.jitsi.org stable/ Translation-en_US
Ign:10 https://download.jitsi.org stable/ Translation-en
Ign:8 https://download.jitsi.org stable/ Packages
Ign:9 https://download.jitsi.org stable/ Translation-en_US
Ign:10 https://download.jitsi.org stable/ Translation-en
Err:8 https://download.jitsi.org stable/ Packages
server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: no
Ign:9 https://download.jitsi.org stable/ Translation-en_US
Ign:10 https://download.jitsi.org stable/ Translation-en
Reading package lists… Done
W: The repository ‘https://download.jitsi.org stable/ Release’ does not have a Release file.
N: Data from such a repository can’t be authenticated and is therefore potentially dangerous to
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch https://download.jitsi.org/stable/Packages server certificate verification f
d. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
E: Some index files failed to download. They have been ignored, or old ones used instead.

How can we solve this problem

Thank you in advance.

Hello @damencho,
Please help me to resolve this issue.
In our machine in path “/var/lib/apt/lists/partial/” following files are avaiable
download.jitsi.org_stable_en.xz
download.jitsi.org_stable_en.lz4
download.jitsi.org_stable_en
download.jitsi.org_stable_en.lzma
download.jitsi.org_stable_en%5fUS
download.jitsi.org_stable_en%5fUS.lz4
download.jitsi.org_stable_Packages
download.jitsi.org_stable_en%5fUS.lzma
download.jitsi.org_stable_Packages.lzma
download.jitsi.org_stable_en%5fUS.bz2
download.jitsi.org_stable_Packages.lz4
download.jitsi.org_stable_Packages.xz
download.jitsi.org_stable_en.bz2
download.jitsi.org_stable_en.gz
download.jitsi.org_stable_Packages.bz2
download.jitsi.org_stable_en%5fUS.xz
download.jitsi.org_stable_en%5fUS.gz
download.jitsi.org_stable_Packages.gz
download.jitsi.org_stable_InRelease
download.jitsi.org_stable_Release

We don’t know why it is creating these many files. in my another PC only following two files was created
download.jitsi.org_stable_Packages
download.jitsi.org_stable_InRelease