W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.ros.org/ros/ubuntu xenial InRelease: The following signatures were invalid: KEYEXPIRED 1622248854..

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.ros.org/ros/ubuntu xenial InRelease: The following signatures were invalid: KEYEXPIRED 1622248854
W: Failed to fetch http://packages.ros.org/ros/ubuntu/dists/xenial/InRelease  The following signatures were invalid: KEYEXPIRED 1622248854
W: Some index files failed to download. They have been ignored, or old ones used instead.

 

 

<해결>

Remove the old key

• on Ubuntu 16.04 and newer (with ROS Kinetic, Melodic, etc)

sudo apt-key del 421C365BD9FF1F717815A3895523BAEEB01FA116

 

• on Ubuntu 15.10 and older (ie: 14.04, from here)

sudo apt-key del B01FA116

 

 

Import the new key

This command should work on all versions of Ubuntu:

# add the new key

sudo -E apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654

 

Final step

At this point make sure to run 

sudo apt clean
sudo apt update.

You should receive no errors and subsequent sudo apt install commands should also now work.

 

 

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https://answers.ros.org/question/325039/apt-update-fails-cannot-install-pkgs-key-not-working/

apt update fails / cannot install pkgs: key not working? - ROS Answers: Open Source Q&A Forum