Ubuntu 18.04
For some time now the graphical GUI Software Updater would report
Then click ok would give me
Then click Install Now
it would report loading for a fraction of a second then close. I should have been suspicious, but ...
Well, today I tried
sudo apt-get update
and got the following error
Get:14 https://packagecloud.io/shiftkey/desktop/any any InRelease
[23.2 kB] Err:14
https://packagecloud.io/shiftkey/desktop/any any InRelease The
following signatures couldn't be verified because the public key is
not available: NO_PUBKEY B7E65990E879472F Reading package lists...
Done W: GPG error: https://packagecloud.io/shiftkey/desktop/any any
InRelease: The following signatures couldn't be verified because the
public key is not available: NO_PUBKEY B7E65990E879472F E: The
repository 'https://packagecloud.io/shiftkey/desktop/any any
InRelease' is not signed.
askubuntu.com/questions/849919/fail-to-sudo-apt-get-update
suggests
sudo apt-get --allow-unauthenticated update
but this fails too.
fix-apt-get-update-the-following-signatures-couldnt-be-verified-because-the-public-key-is-not-available
many more questions with same answer
and more
suggests
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys xxxx
but this fails too "gpg: keyserver receive failed: No data".
Suggestions for what to do next would be appreciated.