Unable to update my ubuntu from focal to jammy

[frnd]

Please help me out
I get this error when trying to update my ubuntu

Updating from such a repository can’t be done securely, and is
therefore disabled by default., W:See apt-secure(8) manpage for
repository creation and user configuration details., W:GPG error:
https://brave-browser-apt-release.s3.brave.com stable InRelease: The
following signatures couldn’t be verified because the public key is
not available: NO_PUBKEY A8580BDC82D3DC6C, E:The repository
‘https://brave-browser-apt-release.s3.brave.com stable InRelease’ is
not signed.

[SmartyAadi]

@JimB1 any help you can provide ?

[JimB1]

Did you follow these instructions exactly? https://brave.com/linux/#debian-ubuntu-mint

One of those steps should insert the Brave repo’s public key into your keyring so it will be known and trusted by apt.

See also Where is the PGP Verification taking place? In Linux CLI commandline installation - #2 by JimB1.

[frnd]

Yes i did but I am still unable to update from ubuntu focal to jammy
I still get this error from updating

Err https://brave-browser-apt-release.s3.brave.com stable InRelease
The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A8580BDC82D3DC6C
Fetched 4,317 B in 0s (0 B/s)

Error during update

A problem occurred during the update. This is usually some sort of
network problem, please check your network connection and retry.

W:Updating from such a repository can’t be done securely, and is
therefore disabled by default., W:See apt-secure(8) manpage for
repository creation and user configuration details., W:GPG error:
https://brave-browser-apt-release.s3.brave.com stable InRelease: The
following signatures couldn’t be verified because the public key is
not available: NO_PUBKEY A8580BDC82D3DC6C, E:The repository
‘https://brave-browser-apt-release.s3.brave.com stable InRelease’ is
not signed.

[JimB1]

Please show the output of the first 3 lines of the Linux install instructions.