I'm reading from here: https://stackoverflow.com/questions/7062521/rsync-exits-with-the-message-stdin-is-not-a-tty
You need to add:
[ -z "$PS1" ] && return
to the beginig of .bashrc that is located in your home dir. That command checks to see if the shell is running interactively. If so, it exits immediately. This makes sense since stuff in the bash configuration file isn't needed for non interactive processes, like rsync
"in your home dir" meaning the user used to login on your @SITEALIAS.live server. So you need to SSH into your server as that user, and add the above line to the beginning of your
~/.bashrc on that server.
An explanation from another answer:
The error message "stdin: is not a tty" is due to something in the startup script on your server attempting to process an action that should only happen for interactive logins (when you connect with ssh direct to the server, etc).