Can<t download the packages when upgrading to the 15.04 version

[Malick]

When trying to upgrade from 14.04 to 15.04 the systeme bug at the second check point which is definition of new repositories

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.16.0-57.77~14.04.1-generic 3.16.7-ckt20
Uname: Linux 3.16.0-57-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Sun Dec 20 22:52:05 2015
InstallationDate: Installed on 2015-05-26 (208 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2015-12-21 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.update.manager.release.upgrades: 2015-12-20T15:48:15.303258

[Brian Murray (brian-murray)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1534374, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.