Cannot run updates on a Mint installation

Questions
1

Before we switched my wife’s HP Envy over to Linux, we did a test installation on a low-price HP laptop to learn how to do it completely before we did “for real” on her main laptop. She has now been on Linux completely for one year! And she loves it.

Now, our “test laptop” is lightly used for smaller purposes, but we cannot run updates on it. We get the following error messages and I have no idea where to start on fixing it. The main laptop has been updating fine so I have no idea why the smaller laptop is having this problem. Same installs were done orginally.

"The repository may no longer be available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and ensure the repository address in the preferences is correct.

An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: Index of /repositories/home:/Provessor/xUbuntu_20.04 InRelease: The following signatures were invalid: EXPKEYSIG 876292BF7F9C32BF home:Provessor OBS Project home:Provessor@build.opensuse.orgFailed to fetch http://download.opensuse.org/repositories/home:/Provessor/xUbuntu_20.04/InRelease The following signatures were invalid: EXPKEYSIG 876292BF7F9C32BF home:Provessor OBS Project home:Provessor@build.opensuse.orgSome index files failed to download. They have been ignored, or old ones used instead."

2

Which Distribution and version of Linux are your running on the ‘test laptop’?

What command are you using to run updates?

Do you use OBS (is it needed on your system) for video recording or streaming?

Did you install OBS or did it come preinstalled with your version of Linux?

3

I somehow didn’t catch that OBS was on those notes. OBS must have been pre-installed because we DO use OBS but that’s on the main laptop. We wouldn’t have installed it on the test laptop because it’s a low-sized hard drive HP and would never be able to handle the file sizes created by a video! So I bet we could just uninstalled OBS and that would take care of it.

Edited: OBS is not installed on the laptop. So I’m not sure why that would even be an issue.

I’m running Mint 20.2 at the moment on this small laptop.

4

So I guess the question is, if I don’t have OBS installed, why is this giving me an error about OBS? And how would I resolve this?

5

I upgraded to Mint 20.3. I’ll see if that gives any issues.

6

You may need to remove the repository for OBS.
The following link tells how to do that from the command line. It may be possible to do that from the GUI software manager but I don’t know how to do that. I assume you are using the Ubuntu version of Mint but Debian and Ubuntu use the same command line tools I believe.
https://help.ubuntu.com/community/Repositories/CommandLine