When trying to upgrade Ubuntu 14.04 to Ubuntu 16.04, after the process starts, when is in the step two "configuring new software channels" (Configurando nuevos canales de software), It stops with the error message "has not been able to calculate the update" (No se ha podido calcular la actualizacion) and "rolls back" to the original state.
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.11
ProcVersionSignature: Ubuntu 3.13.0-170.220-generic 3.13.11-ckt39
Uname: Linux 3.13.0-170-generic i686
NonfreeKernelModules: wl
ApportVersion: 2.14.1-0ubuntu3.29
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Sun May 30 13:58:29 2021
InstallationDate: Installed on 2016-02-09 (1936 days ago)
InstallationMedia: Ubuntu 12.04.5 LTS "Precise Pangolin" - Release i386 (20140807.1)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2021-05-30 (0 days ago)
VarLogDistupgradeTermlog:
From another bug (1909589) I got the tip to run the command "do-release-upgrade -p" and got the attached txt file: "release-