I can't update from ubuntu 18.04 to 20.04

[Juan Carlos Tique Rangel]

Despues de actualizar al 18.04 no me deja pasar al 20.04 a travez del GUI, el error con las instrucciones que me aparecen son:

This was likely caused by:
 * Unofficial software packages not provided by Ubuntu
Please use the tool 'ppa-purge' from the ppa-purge
package to remove software from a Launchpad PPA and
try the upgrade again.

If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If you want to investigate this yourself the log files in '/var/log/dist-upgrade' will contain details about the upgrade. Specifically, look at 'main.log' and 'apt.log'

como se puede leer en las instrucciones trate de usar el software ppa-purge pero no funciono

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.44
ProcVersionSignature: Ubuntu 4.15.0-143.147-generic 4.15.18
Uname: Linux 4.15.0-143-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.23
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity:Unity7:ubuntu
Date: Mon May 24 00:16:37 2021
InstallationDate: Installed on 2021-01-29 (114 days ago)
InstallationMedia: Ubuntu 16.04.7 LTS "Xenial Xerus" - Release amd64 (20200806)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2021-05-24 (0 days ago)
VarLogDistupgradeTermlog:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Brian Murray (brian-murray)]

Thanks for taking the time to report this upgrade failure. There is currently a new version of the release upgrader available which may resolve the error you've encountered. Please run the following command to test the new version of the upgrader:

  do-release-upgrade

Please lets us know the results in this bug report. Thanks again and good luck!

[Launchpad Janitor (janitor)]

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