NO_PUBKEY Issue

Hit:21 http://ppa.launchpad.net/webupd8team/sublime-text-3/ubuntu xenial InRelease
Fetched 1,490 B in 1s (1,302 B/s)                 
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://dl.winehq.org/wine-builds/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 76F1A20FF987672F
W: GPG error: http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0A506F712A7D8A28
W: The repository 'http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: Failed to fetch https://dl.winehq.org/wine-builds/ubuntu/dists/xenial/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 76F1A20FF987672F
W: Some index files failed to download. They have been ignored, or old ones used instead.

wget -nc https://dl.winehq.org/wine-builds/winehq.key && sudo apt-key add winehq.key && sudo apt update

boris@boris-home:~$ wget -nc https://dl.winehq.org/wine-builds/winehq.key && sudo apt-key add winehq.key && sudo apt update
--2019-01-15 00:43:38--  https://dl.winehq.org/wine-builds/winehq.key
Resolving dl.winehq.org (dl.winehq.org)... 151.101.126.217
Connecting to dl.winehq.org (dl.winehq.org)|151.101.126.217|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3220 (3.1K) [application/pgp-keys]
Saving to: ‘winehq.key’

winehq.key          100%[===================>]   3.14K  --.-KB/s    in 0s      

2019-01-15 00:43:38 (77.1 MB/s) - ‘winehq.key’ saved [3220/3220]

OK
Ign:1 http://linux.dropbox.com/ubuntu wily InRelease
Ign:2 http://dl.google.com/linux/chrome/deb stable InRelease                   
Hit:3 http://linux.dropbox.com/ubuntu wily Release                             
Hit:6 http://archive.canonical.com/ubuntu xenial InRelease                     
Hit:7 http://repository.spotify.com stable InRelease                           
Ign:8 http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  InRelease
Hit:9 http://dl.google.com/linux/chrome/deb stable Release                     
Get:10 https://dl.winehq.org/wine-builds/ubuntu xenial/main amd64 Packages [145 kB]
Hit:11 http://ca.archive.ubuntu.com/ubuntu xenial InRelease                    
Hit:12 http://ppa.launchpad.net/fpoussin/ppa/ubuntu xenial InRelease           
Hit:13 http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release
Get:14 https://dl.winehq.org/wine-builds/ubuntu xenial/main i386 Packages [151 kB]
Get:15 http://ca.archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]   
Get:16 http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release.gpg [481 B]
Hit:18 http://ppa.launchpad.net/gezakovacs/ppa/ubuntu xenial InRelease         
Ign:16 http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release.gpg
Hit:19 http://ppa.launchpad.net/mosquitto-dev/mosquitto-ppa/ubuntu xenial InRelease
Get:20 http://ca.archive.ubuntu.com/ubuntu xenial-backports InRelease [107 kB] 
Hit:21 http://ppa.launchpad.net/webupd8team/sublime-text-3/ubuntu xenial InRelease
Hit:22 http://archive.ubuntukylin.com:10006/ubuntukylin xenial InRelease
Reading package lists... Done 
W: GPG error: http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0A506F712A7D8A28
E: The repository 'http://download.opensuse.org/repositories/home:/emby/xUbuntu_16.04  Release' 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.

boris@boris-home:~$ 


You can see the key issue from WinHQ is gone now.

###########################################################

$ sudo -i 

 # apt-get clean 

 # cd /var/lib/apt 

 # mv lists lists.old 

 # mkdir -p lists/partial 

 # apt-get clean 

 # apt-get update

sudo sed -i '/opensuse/ s/^/#/' /etc/apt/sources.list.d/*.list

Now the key issue from opensuse should also be gone.


ref:
https://askubuntu.com/questions/1103320/the-following-signatures-couldnt-be-verified-because-the-public-key-is-not-avai
https://ubuntuforums.org/showthread.php?t=1869890&page=3
https://askubuntu.com/questions/522114/cant-get-rid-of-gpg-error-http-download-opensuse-org