Using the command below fails, with invalid argument.
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ACCAF35C
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ACCAF35C
[sudo] password for *****:
Executing: /tmp/apt-key-gpghome.I5rQFm9bxA/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys ACCAF35C
gpg: keyserver receive failed: Invalid argument
Digging into this, I tried to manually download the certificate and add it, but it appears that the key “ACCAF35” doesn’t exist on the Ubuntu key server, so it cannot be added.
Manual Search on the keyserver.ubuntu.com
https://keyserver.ubuntu.com/pks/lookup?search=ACCAF35&fingerprint=on&op=index
Technically it looks like I can still pull updates, but the error is annoying and this really should be corrected.