Upgrading to Ubuntu 20.04 authentication issue

Following this guide to update to 20.04 https://ubuntu.com/blog/how-to-upgra...0-04-lts-today

Specifically Alternative options to upgrade

Code:sudo update-manager -c
sudo update-manager -c -dBut getting a Authentication failed popup error window. Authenticating the upgrade failed.

Also tried running this line first

Code:sudo apt-get install --reinstall ubuntu-keyringbut no difference.