José, you've reported this issue against Xorg, the display server, why? Are you still experiencing this problem? If so mirror or repository problems should *not* be reported in Launchpad - see https://wiki.ubuntu.com/Bugs/FindRightPackage#Ubuntu_mirror_issues
Have you tried changing your download servers? ** Package changed: xorg (Ubuntu) => ubuntu ** Changed in: ubuntu Status: New => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1759010 Title: Repository authenticity problem Status in Ubuntu: Incomplete Bug description: I can not complete updates ... Delayed and incomplete updates! Difficulty checking the authenticity of repositories ... ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: xorg 1:7.7+1ubuntu8.1 ProcVersionSignature: Ubuntu 3.13.0-37.64-generic 3.13.11.7 Uname: Linux 3.13.0-37-generic i686 ApportVersion: 2.14.1-0ubuntu3.27 Architecture: i386 CurrentDesktop: X-Cinnamon Date: Mon Mar 26 16:05:07 2018 EcryptfsInUse: Yes InstallationDate: Installed on 2017-10-27 (150 days ago) InstallationMedia: Linux Mint 17.1 "Rebecca" - Release i386 20141126 SourcePackage: xorg UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1759010/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp