If after the linux apt update command you receive an error similar to what is seen below:
[email protected]:~# apt update
Get:1 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Ign:2 http://dl.google.com/linux/mod-pagespeed/deb stable InRelease
Hit:3 http://ppa.launchpad.net/ondrej/php/ubuntu focal InRelease
Get:4 http://dl.google.com/linux/mod-pagespeed/deb stable Release [2154 B]
Hit:5 http://de.archive.ubuntu.com/ubuntu focal InRelease
Get:6 http://dl.google.com/linux/mod-pagespeed/deb stable Release.gpg [819 B]
Get:7 http://de.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:8 http://de.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Ign:6 http://dl.google.com/linux/mod-pagespeed/deb stable Release.gpg
Get:9 https://deb.goaccess.io focal InRelease [2345 B]
Err:9 https://deb.goaccess.io focal InRelease
The following signatures were invalid: EXPKEYSIG 97BD1A0133449C3D Gerardo Orellana <[email protected]>
Reading package lists… Done
W: GPG error: http://dl.google.com/linux/mod-pagespeed/deb stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 78BD65473CB3BD13
E: The repository ‘http://dl.google.com/linux/mod-pagespeed/deb stable Release’ is not signed.
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.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://deb.goaccess.io focal InRelease: The following signatures were invalid: EXPKEYSIG 97BD1A0133449C3D Gerardo Orellana <[email protected]>
Then I recommend you try the following command to create a GoAccess-specific keyring:
wget -O - https://deb.goaccess.io/gnugpg.key | sudo apt-key --keyring /etc/apt/trusted.gpg.d/goaccess.gpg add -
then try apt update again!
solution found via: github.com/allinurl/goaccess/issues/1775