While running autoinstaller or execution of
apt-get update command on Debian 8, the following error is shown:
GPG error: http://autoinstall.plesk.com jessie InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY BD11A6AA914BDF7E
Plesk GPG key was not installed.
Fetch and install GnuPG key:
# wget http://autoinstall.plesk.com/plesk.gpg
# sudo apt-key add plesk.gpg