not able to upgrade from 18.04 to 20.04

[bhargav srinivas chinnari]

Says the existing mirror could be very heavy. The upgrade has asked me to look at sources.list.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.40
ProcVersionSignature: Ubuntu 4.15.0-122.124-generic 4.15.18
Uname: Linux 4.15.0-122-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.17
Architecture: amd64
CrashDB: ubuntu
Date: Wed Nov 11 10:21:12 2020
InstallationDate: Installed on 2017-12-04 (1072 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_IN:en
 PATH=(custom, no user)
 LANG=en_IN
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-11-11 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2020-11-11 10:18:14.864825
 Log time: 2020-11-11 10:19:53.549000
 Log time: 2020-11-11 10:20:32.372042
 Log time: 2020-11-11 10:21:14.740223
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

There was an error when the upgrade process was communicating with the mirror of the Ubuntu archive which you use. Please try the upgrade again and see if the mirror is working better, if not I'd suggest switching mirrors of the Ubuntu archive.

2020-11-11 10:20:12,353 DEBUG examining: 'deb http://in.archive.ubuntu.com/ubuntu/ bionic main restricted'
2020-11-11 10:20:12,353 DEBUG verifySourcesListEntry: deb http://in.archive.ubuntu.com/ubuntu/ focal main restricted
2020-11-11 10:20:12,353 DEBUG url_downloadable: http://in.archive.ubuntu.com/ubuntu//dists/focal/Release
2020-11-11 10:20:12,353 DEBUG s='http' n='in.archive.ubuntu.com' p='/ubuntu//dists/focal/Release' q='' f=''
2020-11-11 10:20:12,503 DEBUG error from httplib: 'HTTP Error 500: Internal Server Error'

[Launchpad Janitor (janitor)]

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