Back to My Mac Only Works One Way I've got an interesting problem happening.

From iMac ➔ MacBookPro Back To My Mac works fine.
From MacBookPro ➔ iMac… not so much.  Sometimes I can't even get past the connection piece. It just does that shaky thing that it likes to do when it doesn't accept a password.

When/if I do I get an error message that says the viewer and server are incompatible.



Same network (just to rule out firewall craziness), all items are checked in iCloud etc. I can SSH back and forth. It's only when I try to use file or screen sharing that I see the issue.

Any ideas where I should start? I’m flying blind on this one - no idea why it would work one way and not the other.
I may be jumping the gun here with my answer, but I'm going to assume that one of your Macs is running macOS Mojave and the other is running an earlier version of macOS.

macOS Mojave dropped support for the Back to My Mac feature. Instead, users are encouraged to use iCloud Drive, screen sharing, and Apple Remote Desktop for the various features you may have been using Back to My Mac for.

For more info on this change, refer to Prepare for changes to Back to My Mac on Apple's website.