I want to update Linux Ubuntu 18.04 to 22.04 running on Oracle VM Virtual Box 7.0.20. Though I cannot do it in one step, I have to do it with 2, the first one should be an Update to version 20.04.
I tried it first with the software updater of the desktop. It shows me the following message:
Failed to download repository information. Check Your internet connection.
But on Firefox internet is working perfectly.
Now I tried it on the terminal with
sudo apt-get update
I get the following type of errormessages:
http://snapshot.debian.org/archive/debian-security/20140517T222731Z jessie/updates InRelease The following signatures were invalid: EXPKEYSIG 8B48AD6246925553...
and
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used...
I've already been on many sites, but I cannot find any useful hint.
Could anybody help me..?
Thanks in advance