query: Apt-get update error: http://extras.ubuntu.com Public key unavailable
positive_passages.docid: 6809
positive_passages.text: How do I fix the GPG error "NO_PUBKEY"?
negative_passages.docid: 15183
negative_passages.text: Elementary OS PPA gives “The repository does not have a Release file.” error
negative_passages.docid: 21382
negative_passages.text: What does "sudo apt-get update" do?
negative_passages.docid: 108510
negative_passages.text: apt-get update very slow, stuck at "Waiting for headers"
negative_passages.docid: 95593
negative_passages.text: sudo apt-get update returns an error
negative_passages.docid: 113145
negative_passages.text: What does 'apt-get install update' do?
negative_passages.docid: 93246
negative_passages.text: How to resolve conflicting distributions in apt-get
negative_passages.docid: 122588
negative_passages.text: Can't connect to ubuntu archive when using apt-get update
negative_passages.docid: 4248
negative_passages.text: How to fix apt: Signature by key uses weak digest algorithm (SHA1)?
negative_passages.docid: 30754
negative_passages.text: Cannot update: "No available releases found"
negative_passages.docid: 10633
negative_passages.text: software updater failed to download repository information
negative_passages.docid: 94986
negative_passages.text: Connection Refused while apt-get update ubuntu 18.04 over proxy
negative_passages.docid: 158674
negative_passages.text: How do I get `apt-get update` to work on a machine with no internet access and manually assigned IP address?
negative_passages.docid: 66065
negative_passages.text: "Unable to connect" error with apt-get?
negative_passages.docid: 83924
negative_passages.text: error while trying to sudo apt-get update GPG, no sign repository
negative_passages.docid: 124605
negative_passages.text: Apt server certificate error with download.01.org
negative_passages.docid: 75879
negative_passages.text: How do I get add-apt-repository to work through a proxy?