Odd connection problem

[Dlass]

I'm trying to connect computer A and computer B. A is a 2011 MacBookPro running 10.13.3. B is a 2020 M1 iMac running 14.3.1. I have the same usernames for my accounts on all of my machines. I have no trouble on B connecting to A. Works flawlessly. I can access all my files and folders on A, when using B. But when I try to connect to B from A, by selecting B in the Network menu, I get "Connection Failed". I try to "Connect As" in that window, but it refuses to respond to that request. I'm not asked for any input, Nothing happens. Oddly, from A, I have no trouble screen sharing when I select B in the Network window, and then hit "Share Screen". On A, I can then see the screen on B just fine. So A certainly knows that B is there."File Sharing" is enabled on both machines. A just won't connect to B in the Finder for file sharing. These machines are both connected to the same router, which is why each machine shows up in their Finder sidebars. They're on the same network. FWIW, I can easily connect to A and B from computer C in another room. Also FWIW, I can easily connect to C from A and B, and I can easily connect to C from B. There are no Firewalls set up anywhere, BTW.

So what am I doing wrong? How can I connect to B from A? I'm told "Connection Failed", but I have no idea why.

 

[MacsBug]

I just tried this on a similar setup. I do however have 10.13.6 installed on my 2011.

You may want to upgrade High Sierra to 10.13.6 and the latest security update (2020-006) and then see if this fixes your issue.

Here are the download links for the 2 updates.

macOS High Sierra 10.13.6 Combo Update: https://support.apple.com/en-us/106398

Security Update 2020-006 (High Sierra): https://support.apple.com/en-us/106521

 

[Dlass]

Sorry, my mistake. A *is* at 10.13.6. Well, turns out that security update had not been done, as per System Report->Installations. So I did it, and it was kind of painful, getting hung up for hours at a time, and rebooted unsuccessfully once or twice. But finally got it rebooted, the update was successful and, I am blown away, now it all works. I can connect.

To be honest, it is hard to say whether it was the security update or just a reboot that fixed it. I should have tried the latter first. Not clear what a reboot would have cleared to fix it, though. So thanks for giving me the initiative to do all that!