Issue apt cache fetch failed / Package update manager notification

[carlos.pacheco@nanode]

Server operating system version

Ubuntu 22.04

Plesk version and microupdate number

Plesk Obsidian 18.0.67

I have an error every day with automatic updates, I receive notifications every morning with error message like this:

Hola, Administrator: Ha habido un error con la actualización de los paquetes del sistema y los componentes de terceros del servidor condescending-jackson.74-208-141-75.plesk.page. Espere a la siguiente actualización automática o ejecute la actualización manualmente: https://74.208.86.98:8443/admin/pum Motivo: 2026-06-17 06:25:44 INFO: pum is called with arguments: ['--list', '--repo-info', '--json'] 2026-06-17 06:25:46 ERROR: Apt cache fetch failed: W:GPG error: Index of /pool/PSA_18.0.66_16134 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY BD11A6AA914BDF7E, E:The repository 'Index of /pool/PSA_18.0.66_16134 noble InRelease' is not signed., W:Updating from such a repository can't be done securely, and is therefore disabled by default., W: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: Index of /PHP74_17 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9299045CE550E57, W:An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: Index of /PHP82_17 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9299045CE550E57, W:An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: Index of /PHP83_17 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9299045CE550E57 2026-06-17 06:25:46 ERROR: W:GPG error: Index of /pool/PSA_18.0.66_16134 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY BD11A6AA914BDF7E, E:The repository 'Index of /pool/PSA_18.0.66_16134 noble InRelease' is not signed., W:Updating from such a repository can't be done securely, and is therefore disabled by default., W: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: Index of /PHP74_17 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9299045CE550E57, W:An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://autoinstal l.plesk.com/PHP82_17 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9299045CE550E57, W:An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: Index of /PHP83_17 noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9299045CE550E57 2026-06-17 06:25:46 ERROR: Exited with returncode 1.​

 

[alapshin]

Hello @carlos.pacheco@nanode
It seems server has issue with GPG key for packet manager, try to apply the solution from the article
Unable to update Plesk: The following signatures couldn't be verified because the public key is not available

 

[nmdpa3]

Were seeing the same error on updates to ubuntu systems, 3 days in a row now they are failing

 

[scsa20]

You still need to update the public key with the new key on all servers affected by following the steps provided by @alapshin

 

[nmdpa3]

So, just to make sure I understand this correctly: Plesk introduced a bug in a previous update, and now we get the privilege of cleaning it up?

 

[nmdpa3]

Err:19 Index of /mariadb/repo/10.6/ubuntu/ jammy InRelease
Cannot initiate the connection to mirror.docker.ru:443 (2a04:8580:ffff:fffe::2). - connect (101: Network is unreachable) Could not connect to mirror.docker.ru:443 (185.253.23.31), connection timed out

Related or no?

 

[Sebahat.hadzhi]

@nmdpa3 ,no, this looks like a network/connectivity issue rather than the originally reported GPG issue. I would recommend checking your IPv6 configuration and testing the connection with:

curl -6 https://mirror.docker.ru

 

[nmdpa3]

@nmdpa3 ,no, this looks like a network/connectivity issue rather than the originally reported GPG issue. I would recommend checking your IPv6 configuration and testing the connection with:

curl -6 https://mirror.docker.ru

...after 18.0.78 update #4 this is no longer happening for us.