What to do with KEYEXPIRED 1555048520 on updating Google Chrome and Earth repositories?

Solution 1:

It's fixed on Google's end now, so you can update normally through apt without workarounds.

(Sorry, can't comment due to <50 reputation.)

Solution 2:

Current status on Ubuntu 16.04 LTS:

• Google Chrome repository updated successfully.
• Google Earth repository updated successfully.

If you still have issues - then remove GPG keys and re-add GPG key into the system with

sudo apt-key del D38B4796
sudo apt-key del 7FAC5991
wget -q -O - https://dl.google.com/linux/linux_signing_key.pub | sudo apt-key add -

or

sudo apt-key net-update
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys D38B4796
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 7FAC5991
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 1397BC53640DB551

and update package lists:

sudo apt-get update