Thanks!
Big Sur does not support AFP, hence the need to use Samba for both macOS and Windows shares.
As I said above, I'm not given any opportunity TO log-in. It gives the error without pulling up the dialogue box to login. I've read elsewhere this could be a NetBIOS issue, which I then enabled on the Mac Mini, but to no avail.
I WAS finally able to get it to work with Windows, including pulling up the login and being able to log-in, by enabling SMB 1.0 in Windows.
Thanks!
Yeah as I mentioned above, the issue here isn't running one older version of macOS with another older version of macOS. It was working before, though I hadn't used it in a while. It doesn't appear to work with Big Sur. From what I can glean, it may be because for security reasons, Big Sur refuses to accept any SMB 1.0 connections and I've found some ways around that but they haven't worked for me unfortunately. I'll keep trying. I WAS able to enable SMB 1.0 on Windows and get that working; so that may just have to be a solution; using a 'bridge' solution like
@eyoungren suggested.
Yep. I've used FreeNAS in the past and it's fantastic! I may consider it again. I'm using the Mac Mini because it's easy to use and some of the macOS specific features are pretty cool; but Apple has actually removed a lot of those. And some (like pre-downloading software updates for all of my devices) are no longer relevant to me (I went from a 3mbps internet connection to gigabit last year! Thank you, expanding fiber!). That particular feature was a GODSEND when the only option I have was an antiquated DSL connection.
Though I've found the software I use for both syncing other machines (Syncthing) and cloud backup (Crashplan) work the best with fewest issues on macOS, which is another reason I've really appreciated having a macOS "home server". Unlike when I've had FreeNAS as my home server OS, or even Windows 7 (Or XP or... Windows 98 and Windows 2000 if we go back far enough!), when I started using this Mac Mini a couple years ago as my home server it has been the most problem free home server I've ever had. I don't think about it, I don't mess with it, I don't touch it. It just 'exists' on a shelf plugging away quietly. I updated to Big Sur just to keep things up to date and secure, but didn't realize it was going to break compatibility with my vintage macs.
Yeah, Windows can be a PITA for sure. Ironically, right now Windows is the only thing I can connect to. (I will say, Windows 10 is the best implementation of Networking on Windows I've ever used) One of the very few things Windows does better than macOS is backwards compatibility. I've got software that's 2 or 3 years old that won't run on my Mac. I occasionally fire up Windows 9x era games on my Windows 10 PC and they just run. Plus you can dig through the 'windows features' window and add functionality that's been defunct for decades... like, for example, Samba 1.0!