Schleuder is failing to send email

Email was sent on network-team-security@ yesterday and the stacktrace received by the sender was:

<network-team-security-sendkey@lists.torproject.org>: Command died with status
    126: "/srv/schleuder.torproject.org/bin/schleuder". Command output:
    /srv/schleuder.torproject.org/bin/schleuder:
    /home/torschleuder/.gem/ruby/2.3.0/bin/schleuder: /usr/bin/ruby2.3: bad
    interpreter: No such file or directory