Can't install VLC package from the PPA "The following signatures couldn't be verified because the public key is not available"
3298
How do I resolve unmet dependencies after adding a PPA?
109677
How do I to resolve unmet dependencies to uninstall and reinstall package
158683
apt-get update failed because certificate verification failed because handshake failed on nodesource
40885
What should I do when I got the KEYEXPIRED error message after an apt-get update?
3523
What does "Package  has no installation candidate" mean?
43579
I cannot install new packages: "Could not get lock /var/lib/dpkg/lock"
151694
Can't install pipelight ubuntu 16.04
152823
PPAs will not install "sudo: add-apt-repository: command not found"
45921
VLC will not install 14.04
6105
What is the easiest way to resolve apt-get BADSIG GPG errors?
151066
Failed to fetch PPA Error (Deluge)
109277
Can't Add ppa:x2go/stable
92884
How to update VLC to the latest version?
126437
pass and gpg: No public key
86898
How to solve missing libmng.so.1 in Trusty (14.04) Package is no more available
1632
How do I fix a "Failed to download package files" error?
21483
no such file or directory 'authorized_keys'