[Koha] koha installation error

[Tom Obrien]

Greetings,
I upgraded ubuntu server 16 LTS to 22 LTS.
I am trying to install koha but I get the following error:
wget -O- https://debian.koha-community.org/koha/gpg.asc | sudo apt-key add -
--2023-11-13 06:30:33--  https://debian.koha-community.org/koha/gpg.asc
Resolving debian.koha-community.org (debian.koha-community.org)... failed:
Temporary failure in name resolution.
wget: unable to resolve host address ‘debian.koha-community.org’
Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d
instead (see apt-key(8)).
gpg: no valid OpenPGP data found.


Kindly assist me on how to overcome this problem.
Thank in advance.
Tom