cPanel installation fails on Ubuntu if apt-key command fails

Symptoms

cPanel installation returns one or more of the following errors:

1. GPG key is not downloaded

   CONFIG_TEXT: gpg could not recv-keys “3A79BD29” from keyserver.ubuntu.com
   gpg could not recv-keys “3A79BD29” from keyserver.ubuntu.com
   gpg could not recv-keys “5072E1F5” from keyserver.ubuntu.com
   gpg could not recv-keys “5072E1F5” from keyserver.ubuntu.com
   gpg could not recv-keys “C74CD1D8” from keyserver.ubuntu.com

2. The repository is not signed:

   CONFIG_TEXT: [2025-08-22 00:20:37 +0000] W: GPG error: https://dlm.mariadb.com/repo/
   mariadb-server/10.11/repo/ubuntu jammy InRelease: The following signatures 
   couldn't be verified because the public key is not available: 
   NO_PUBKEY F1656F24C74CD1D8
   [2025-08-22 00:20:37 +0000] E: The repository 'https://dlm.mariadb.com
   /repo/mariadb-server/10.11/repo/ubuntu jammy InRelease' is not signed.

3. Background process failed to stage EA4 ( MariaDB needs to be installed first in order to install EA4 ):

   CONFIG_TEXT: [2025-08-22 00:22:46 +0000] [20061] (FATAL): The background process “EA4 Install” 
   failed with a fatal error: The subprocess reported error number 127 when it ended.

Cause

Installing MariaDB/MySQL is required to install cPanel's EasyApache 4. If MySQL/MariaDB fails to install, the rest of the installation will be incomplete and return a failure. This type of failure will also generally require reimaging the server. Recently, it was observed that many failed installations happen during the installation of MariaDB due to the missing GPG key. 

We've opened an internal case for our development team to investigate this further. For reference, the case number is CPANEL-48815. Follow this article to receive an email notification when a solution is published in the product. 

Resolution

Allow port "11371" outgoing in the firewall. Then run the following command to rewrite the key to confirm the default MariaDB key installs successfully:

# apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F1656F24C74CD1D8

Note: If the installation has already failed, be sure to reimage the server and test the command before running the installer once more.

Successful import returns the following output:

CONFIG_TEXT: gpg: key F1656F24C74CD1D8: public key "MariaDB Signing Key <signing-key@mariadb.org>" imported
gpg: Total number processed: 1
gpg:               imported: 1