Hi @Fred,
judging by your screenshot and the gpg: keyserver receive failed: No name error, it seems there is some connection issue between your machine and the Ubuntu keyserver, or the keyserver itself is flaky, which is a common issue, unfortunately 
.
As a workaround, you can also download the GPG key from our package server dl.k6.io, and then import it into the keyring. The complete installation instructions in that case would be:
sudo gpg -k
curl -fsSLO https://dl.k6.io/key.gpg
sudo gpg --no-default-keyring --keyring /usr/share/keyrings/k6-archive-keyring.gpg --import key.gpg
echo "deb [signed-by=/usr/share/keyrings/k6-archive-keyring.gpg] https://dl.k6.io/deb stable main" | sudo tee /etc/apt/sources.list.d/k6.list
sudo apt-get update
sudo apt-get install k6
The important thing you should see in the output is:
gpg: keybox '/usr/share/keyrings/k6-archive-keyring.gpg' created
gpg: key 77C6C491D6AC1D69: public key "k6.io (key for signing binaries) <security@k6.io>" imported
gpg: Total number processed: 1
gpg: imported: 1
From your screenshot I see that you have added the correct key to the /etc/apt/trusted.gpg keyring, but not to the /usr/share/keyrings/k6-archive-keyring.gpg keyring which is specified in the APT sources list. I reckon that if you change the signed-by value in /etc/apt/sources.list.d/k6.list to be /etc/apt/trusted.gpg, you would be able to install k6 without an issue as well.
Hope this helps!