I'm trying to upgrade ubuntu from 18.4 to 20 with terminal command and not working

[Ahmed]

After updating your package information, the essential package
'ubuntu-minimal' could not be located. This may be because you have
no official mirrors listed in your software sources, or because of
excessive load on the mirror you are using. See /etc/apt/sources.list
for the current list of configured software sources.
In the case of an overloaded mirror, you may want to try the upgrade
again later.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.37
ProcVersionSignature: Ubuntu 4.15.0-117.118-generic 4.15.18
Uname: Linux 4.15.0-117-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.16
Architecture: amd64
CrashDB: ubuntu
Date: Tue Sep 15 00:04:13 2020
InstallationDate: Installed on 2018-05-19 (849 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-09-14 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2020-09-12 19:17:29.294063
 Log time: 2020-09-12 19:17:33.546554
 Log time: 2020-09-15 00:04:04.277440
 Log time: 2020-09-15 00:04:15.071981

[Brian Murray (brian-murray)]

Reviewing the log file, /var/log/dist-upgrade/main.log, from your upgrade attempt there was a failure to communicate with the mirror of the Ubuntu archive which you use. This could either be due to an issue with your connection to the mirror or with the mirror itself. Regardless, this is an issue you'll need to sort out before upgrade can complete. If after resolving the communication error with the mirror you are still unable to upgrade to a new release of Ubuntu please open a new bug report so we'll have fresh log files. Thanks and good luck!

[Launchpad Janitor (janitor)]

[Expired for ubuntu-release-upgrader (Ubuntu) because there has been no activity for 60 days.]