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Resolved PPE - repository GPG Error

LRLD

New Pleskian
Server operating system version
Ubuntu 24.04.2
Plesk version and microupdate number
Plesk Obsidian 18.0.70 Update #2 Web Pro Edition
Hi,

as the title suggests, I'm currently getting the following error...

Code:
Err:14 https://mirror.apheleia-it.ch/repos/Kolab:/16/Ubuntu_24.04_Plesk_17  InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
Fetched 1,037 kB in 1s (1,490 kB/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
5 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: https://mirror.apheleia-it.ch/repos/Kolab:/16/Ubuntu_24.04_Plesk_17  InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
W: Failed to fetch https://mirror.apheleia-it.ch/repos/Kolab:/16/Ubuntu_24.04_Plesk_17/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
W: Some index files failed to download. They have been ignored, or old ones used instead.

I do see a kolab.gpg in /etc/apt/trusted.gpg.d, but there's nothing in the /etc/apt/keyrings folder.
Any ideas?

TIA
 
Have you tried downloading the key?

Bash:
sudo gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C8B3DA4DF6491D3D
sudo apt clean
 
Right, it looks like the wrong key is being downloaded and saved to /etc/apt/trusted.gpg.d/kolab.gpg

gpg --show-keys /etc/apt/trusted.gpg.d/kolab.gpg
pub rsa4096 2018-05-24 [SC] A21E96611060CF0B4DF11E64A01D0CA80038D0DB

pub rsa4096 2018-05-24 [SC] A21E96611060CF0B4DF11E64A01D0CA80038D0DB

But the actual signing key is located...

pub rsa2048 2025-07-08 [SC] [expires: 2027-09-16] 9D4C22FDC7E02EA49CF3DB38C8B3DA4DF6491D3D

But it's not available as a .gpg file, just the plain text Release.key, which apt doesn't like.
There is a Release.gpg but that is just a signature file.

TIA
 
Have you tried downloading the key?

Bash:
sudo gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C8B3DA4DF6491D3D
sudo apt clean

Hi mate, yes, I tried that but...

gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C8B3DA4DF6491D3D
gpg: keyserver receive failed: No data

It's only available in the repository (see above) as a plain text public key, it needs to be a .gpg file...not human-readable plain text.

Plesk Premium Email is a paid for extension, I shouldn't have to be playing hunt the repo key, lol!

Hopefully someone at Plesk sees this.

Thanks for your help.
 
Same problem, while researching for an update to 22.04 (and then 24.04) I took a look at the update log and sure enough, the result of a sudo apt update command shows:
Code:
Err:20 https://mirror.apheleia-it.ch/repos/Kolab:/16/Ubuntu_20.04_Plesk_17  InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
Reading package lists... Done
W: GPG error: https://mirror.apheleia-it.ch/repos/Kolab:/16/Ubuntu_20.04_Plesk_17  InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
E: The repository 'https://mirror.apheleia-it.ch/repos/Kolab:/16/Ubuntu_20.04_Plesk_17  InRelease' 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.

I tried exporting and downloading the key. Both commands failed.
Code:
root@server:/etc/apt/sources.list.d# sudo gpg --export C8B3DA4DF6491D3D | sudo tee /etc/apt/trusted.gpg.d/Kolab.gpg
gpg: WARNING: nothing exported

Code:
root@server:/etc/apt/sources.list.d# sudo gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C8B3DA4DF6491D3D
gpg: keyserver receive failed: No data

As has been stated, Premium Email is a paid for extension which we kind of expect to work.
 
I was going to edit my original post, but it seems that isn't possible, so..

This issue seems very similar to that being discussed here, does it not:
 
Have you already tried:



If not, please give it a go and let us know if it solves the issue.
The result of that command :(
Code:
root@server:~# apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C8B3DA4DF6491D3D
Executing: /tmp/apt-key-gpghome.ealtRK3qJC/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys C8B3DA4DF6491D3D
gpg: keyserver receive failed: No data
 
Everyone, could you please try the following:

  1. Backup the kolab.list repository file:
    Bash:
    cp /etc/apt/sources.list.d/kolab.list{,.bak}
  2. Execute the following command:
    Bash:
    while (true); do sed -i "s/deb https/deb [trusted=yes] https/g" /etc/apt/sources.list.d/kolab.list; sleep .5; done
  3. Proceed with the update.
  4. Restore the original repository file after the update:
    Bash:
    mv /etc/apt/sources.list.d/kolab.list.bak /etc/apt/sources.list.d/kolab.list
 
Thank you for your help Sebahat.hadzhi I haven't received the error since yesterday morning, so I didn't get chance to try the above solution.
Thanks again
 
Everyone, could you please try the following:

  1. Backup the kolab.list repository file:
    Bash:
    cp /etc/apt/sources.list.d/kolab.list{,.bak}
  2. Execute the following command:
    Bash:
    while (true); do sed -i "s/deb https/deb [trusted=yes] https/g" /etc/apt/sources.list.d/kolab.list; sleep .5; done
  3. Proceed with the update.
  4. Restore the original repository file after the update:
    Bash:
    mv /etc/apt/sources.list.d/kolab.list.bak /etc/apt/sources.list.d/kolab.list

This does not work because the installed kolab.list file does not contain a string 'deb https'

The contents of this file are:
deb [signed-by=/etc/apt/trusted.gpg.d/kolab.gpg] https://mirror.apheleia-it.ch/repos/Kolab:/16/Debian_12.0_Plesk_17/ /

Manually setting this to be deb [trusted=yes] https.... does not resolve the issue.

This problem still exists and has been in failing for two days for me now

apt-get update returns the following

Get:21 https://mirror.apheleia-it.ch/repos/Kolab:/16/Debian_12.0_Plesk_17 InRelease [1549 B]
Err:21 https://mirror.apheleia-it.ch/repos/Kolab:/16/Debian_12.0_Plesk_17 InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
Reading package lists... Done
W: GPG error: https://mirror.apheleia-it.ch/repos/Kolab:/16/Debian_12.0_Plesk_17 InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C8B3DA4DF6491D3D
E: The repository 'https://mirror.apheleia-it.ch/repos/Kolab:/16/Debian_12.0_Plesk_17 InRelease' 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.

Making this matter worse this breaks to auto updater so now my plesk instance is unable to update at all.
 
Ditto..The GPG error resolved itself and following an update / upgrade the server installed the latest kolab / roundcube.

One small issue though, the kolab and roundcube upgrade broke my Plesk Premium Email ActiveSync :(

Attempts by the mail client were met with NGINX 500 errors for both sync and ping commands.

I did try a full uninstall and re-install of PPE but was forced to go log hunting. I was merely checking if a re-installation would resolve the issue, it didn't.

After reviewing the logs, kolab was unable to find two columns in the roundcubemail SQL DB (within the syncroton_device table) named "is_broken" and "extra_data".

I had to shorten the length of some other varchar columns before it would add "is_broken". "extra_data" was added as a blob without issue.

Once those two columns had been restored, ActiveSync was fully operational again with no more 500 errors in the log.

I'm not quite sure what happened, although MariaDB [10.3.39] is reporting an upgrade is available.
I'm not sure I should do that though considering the 20.04 LTS environment while I evaluate the options on the server.
(as it's probably better to clone the server across to a new Ubuntu instance rather than faff about updating it and then fix everything that breaks lol)

Thanks for the assistance all the same though :)
 
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