Hi guys, I'm wondering if someone will be able to possibly assist with this one. I did a fresh install of Zorin OS, loving it so far.
With a bit of teeth-pulling I managed to get the ProtonVPN CLI installed, and its working BUT I have noticed whenever I run sudo-apt get update, I get the following output concerning ProtonVPN........
'Err:4 https://repo.protonvpn.com/debian stable InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 71EB474019940E11'
It then says this at the end........
'Reading package lists... Done
W: GPG error: https://repo.protonvpn.com/debian stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 71EB474019940E11
E: The repository 'https://repo.protonvpn.com/debian stable InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.'
Would someone be able to assist in how I can rectify this apparent public key issue?
Thanks in advance for all assistance 
Matchwood

