mkdir /run/user/YOURUID
/run is not a thing on macOS. /var/run is but requires root access. The default
socket location on macOS is
iMac-TMP:~ joe$ ls -al /tmp/com.apple.launchd.OWt2QNcw7V total 0 drwx------ 2 joe wheel 102 Mar 1 21:13 . drwxrwxrwt 76 root wheel 2686 Mar 2 00:44 .. srw-rw-rw- 1 joe admin 0 Mar 1 21:13 Listeners
One such directory and socket are created for each user when using ssh.
Note that I had tried hacking in /usr/local/var/run in place of your /run, and
creating the directory, etc., which the test did proceed to use but it didn't
resolve the problem. (I had done that before reporting here.)