[exim] Permission denied when connecting to the SASL AUTH da…

Help! I don't know why this isn't working but quick background:

Wanted to be able to encrypt messages using TLS so I turned it on the the
/etc/exim4/exim4.conf.template file, generated a certificate and found
that I could send messages from console just fine. But whenever I try to
authenticate against the SASL daemon running on the server it continues to
reject my password with the main part of the message being:

cannot connect to saslauthd daemon at /var/run/saslauthd/mux: Permission
denied

As far as I remember SASL is getting it's authentication information from
the /etc/passwd file, correct?

If not then what does it authenticate against and what have I missed?

Thanks in advance,

Jon