New M2 shows with question mark in Finder Network/shared location on old 2010 Mini (but not on MacBook Pro)

Both Macs have now been rebooted, but the new M2 Mini is still showing up on the old mini with a question mark.

Where do I check on the SMB/AFP? I don't remember where that is in settings? Is that settings on the new M2 or the old Mini?

On the old Mini, I have the option to turn on both SMB and AFP. Should both be on or just one of the two?

What is the difference between file sharing using SMB vs. AFP?

On the new M2 Mini, I'm only seeing place to select SMB. If I type AFP into the System Settings search bar, it takes me to the Settings>General>Sharing>File Sharing section, but I don't see the "AFP" anywhere in that section including in the option box.

I guess, none of this is a very big deal. I still seem to be able to do what I need to. I can use either the "Screen Sharing" app or TeamViewer to view, share screen, and control both computers. I seem to be able to manipulate through the finder to access files in either computer. And I seem to be able to then drag files into either the iCloud drive to access from the other computer or to simply drag or copy/paste from one to another.

So I think everything is working, it's just curious and annoying to see the question mark as the icon for the M2 Mini computer when viewing it on the sidebar (or network) section on the older Mini. It just made me think that I had something set up wrong or that I had something wrong with that computer.

I thought I had turned it on, but I guess I hadn’t. I turned it on, but I’m still seeing it old Mini with a question mark. It may resolve itself over time. Maybe a reboot?