I've done a fair bit of testing to try and reproduce the connecting issue you are both having. So far, I've had no luck. The only time I was able to get a "permission denied" error was when I tried to connect with a username/password that didn't match the user currently logged into the PC.
Could you both run the following command on your machines (changing "[username]" as appropriate), and let me know what you get back?
This command is similar to the command that is failing when Tesla is connecting to your machine, hopefully we'll get something a bit more descriptive than what Tesla is reporting.
ssh [username]@localhost "grep DBUS_SESSION_BUS_ADDRESS= ~/.dbus/session-bus/*-0 | cut -d '=' -f 2,3,4"