E: The repository 'http//archive.canonical.com precise Release' is not signed
23819
"GPG error: Release: The following signatures were invalid: BADSIG"
63320
Ubuntu repository does not have a Release file
69037
How to use https with apt-get?
64509
Can't update from official repositories [Error 409]
113379
Updating the repository isn't working
339
How to resolve "Failed to download repository information"?
49149
How do I solve "Unable to fetch some archives, maybe run apt-get update or try with --fix-missing" error?
110896
Package installation - Outdated repository
124576
Unable to download from an authenticated webserver
61177
How to set up an APT repository?
85988
How to set up an apt-cacher server?
10633
software updater failed to download repository information
155198
What is the difference between the "jessie" and "jessie-updates" distributions in /etc/apt/sources.list?
107340
"Invalid signature file" when attempting to run a .jar
48418
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn't be verified because the public key is not available:
33328
apt-get stuck at 0 [Connecting to us.archive.ubuntu.com]
54571
How do I install the latest version of Git with apt?