So I can screen share between the two Macs; I can ssh, rsync, and scp the files between the two Macs; but having Finder try to “Connect As” always fails the login sheet using the same user and password as on the command line.
I tried switching between SMP, SMP encrypted, and AFP ... makes no difference. Authentication? Always fails. Shakes it head at User and password validated as above.
Both Catalina systems were upgraded from previous OS X / MacOS versions, but both client and server accounts are new.