W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://updates.atomicorp.com/channels/tortix-common/ubuntu bionic Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FFBD5D0A4520AFA9
W: Failed to fetch https://updates.atomicorp.com/channels/tortix-common/ubuntu/dists/bionic/Release.gpg  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FFBD5D0A4520AFA9

Issue

In Ubuntu 18.04 bionic, apt update throws the above error during Ubuntu package update process. The fix given on Cpanel.com doesn’t work because the issue isn’t with apt-key.

How to fix

Make sure to run the below commands with root using sudo su.

First, check the Atomicorp apt source file.

sudo cat /etc/apt/sources.list.d/tortix-common.list

deb [signed-by=/usr/share/keyrings/RPM-GPG-KEY.atomicorp.txt arch=amd64] https://updates.atomicorp.com/channels/tortix-common/ubuntu bionic main

Second, check if RPM-GPG-KEY.atomicorp.txt exists.

cat /usr/share/keyrings/RPM-GPG-KEY.atomicorp.txt

cat: /usr/share/keyrings/RPM-GPG-KEY.atomicorp.txt: No such file or directory

If the RPM-GPG-KEY.atomicorp.txt doesn’t exist, grab the file from Atomicorp website.

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.5 (GNU/Linux)
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=DrwN
-----END PGP PUBLIC KEY BLOCK-----

Create the RPM-GPG-KEY.atomicorp.txt in the Keyrings.

nano /usr/share/keyrings/RPM-GPG-KEY.atomicorp.txt

Copy the PGP Public key above or Atomicorp website to the file and Ctrl + X or Cmd + X to save and exit.

Finally, update & upgrade Ubuntu.

apt update && apt upgrade