I cant upgrade my ubuntu version and other programs. Errors show server mirrors' problems.

[Yanes Kerasiotis]

I tried solutions found at digital ocean and ask ubuntu, but none of them helped.

https://www.digitalocean.com/community/questions/cannot-update-to-19-04-the-essential-package-ubuntu-minimal-could-not-be-located-2?answer=51260

https://askubuntu.com/questions/1231817/invalid-package-information-error-when-upgrading-to-ubuntu-20-04

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.32
ProcVersionSignature: Ubuntu 5.4.0-73.82-generic 5.4.106
Uname: Linux 5.4.0-73-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.17
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
Date: Thu Mar 16 17:56:43 2023
InstallationDate: Installed on 2021-04-09 (706 days ago)
InstallationMedia: Ubuntu 18.04.5 LTS "Bionic Beaver" - Release amd64 (20200806.1)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2023-03-16 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2023-03-16 17:56:10.011036
 Log time: 2023-03-16 17:56:14.662660
 Log time: 2023-03-16 17:56:43.382580
 Log time: 2023-03-16 17:56:45.608317

[Nick Rosbrook (enr0n)]

Your mirror does not have information for the Jammy release:

2023-03-16 17:56:27,981 DEBUG examining: 'deb http://ftp.ntua.gr/ubuntu/ focal main restricted'
2023-03-16 17:56:27,982 DEBUG verifySourcesListEntry: deb http://ftp.ntua.gr/ubuntu/ jammy main restricted
2023-03-16 17:56:27,982 DEBUG url_downloadable: http://ftp.ntua.gr/ubuntu//dists/jammy/Release
2023-03-16 17:56:27,982 DEBUG s='http' n='ftp.ntua.gr' p='/ubuntu//dists/jammy/Release' q='' f=''
2023-03-16 17:56:28,054 DEBUG error from httplib: 'HTTP Error 404: Not Found'

Please choose a different mirror of the Ubuntu archive, and then try the upgrade again.

[Yanes Kerasiotis (yanesker)]

I did change to a few others including the main ubuntu server, but it resulted in the same error

[Nick Rosbrook (enr0n)]

You should not have the cdrom source enabled, and it sounds like your octave PPA does not have information for the release either. Please drop those sources and then try again. If you continue to have issues, please open a new bug report with the latest logs.

[Yanes Kerasiotis (yanesker)]

Thanks to your help my issue is now solved, I appreciate your contribution.