"The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192" [duplicate]

Solution 1:

Option 1

From here:

sudo apt-get install --reinstall ubuntu-extras-keyring

Option 2

See here.

Summary:

Open the terminal and run the following commands:

gpg --keyserver keyserver.ubuntu.com --recv 3E5C1192
gpg --export --armor 3E5C1192 | sudo apt-key add -
sudo apt-get update