sudo apt update An error occurred during the signature verification

Question

How do I solve this sudo apt update error?

Err:9 http://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04  InRelease
  The following signatures were invalid: EXPKEYSIG 23E07629B9E3C9E4 home:pzz OBS Project <home:pzz@build.opensuse.org>
Fetched 2,441 B in 3s (819 B/s)
Reading package lists... Done
Building dependency tree       
Reading state information... Done
19 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04  InRelease: The following signatures were invalid: EXPKEYSIG 23E07629B9E3C9E4 home:pzz OBS Project <home:pzz@build.opensuse.org>
W: Failed to fetch http://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04/InRelease  The following signatures were invalid: EXPKEYSIG 23E07629B9E3C9E4 home:pzz OBS Project <home:pzz@build.opensuse.org>
W: Some index files failed to download. They have been ignored, or old ones used instead.

I have tried solutions from post How do I fix the GPG error "NO_PUBKEY"? but they did not work:

$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 23E07629B9E3C9E4
[sudo] password for master: 
Executing: /tmp/apt-key-gpghome.QYq1pmnpyE/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys 23E07629B9E3C9E4
gpg: keyserver receive failed: Server indicated a failure
$ gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv ^C
$ 23E07629B9E3C9E4^C
$ gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv 23E07629B9E3C9E4
gpg: keyserver receive failed: No data

Not a duplicate: The target Q&A addresses the absence of key, however, here key is expired. Here [The following signatures were invalid: EXPKEYSIG 1397BC53640DB551](https://askubuntu.com/q/1133199/816190) is related Q&A, I believe. — Kulfy, Feb 12 '22 at 10:46

N0rbert · Accepted Answer · 2022-02-11T17:06:52.047

2

You have added some thirdparty repository to the system. For now its key is expired.

So you have to disable this repository using Software & Updates.

edited Feb 11 '22 at 17:06

answered Feb 11 '22 at 17:01

N0rbert

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It worked. But how do i actually fix the invalid key issue? Is this something for me to do or for the software developer to fix? – Sun Bear Feb 11 '22 at 20:14
Fix from software developer is needed. – N0rbert Feb 11 '22 at 20:15
Noted. I will inform the developer. – Sun Bear Feb 11 '22 at 20:17

score 0 · Answer 2 · answered Apr 15 '22 at 20:13

Just update the expired gpg key:

curl -fsSL https://download.opensuse.org/repositories/home:pzz/xUbuntu_20.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_pzz.gpg > /dev/null

source: https://software.opensuse.org/download.html?project=home%3Apzz&package=sane-airscan

sudo apt update An error occurred during the signature verification

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