smtp.frontier.com and exim4

[mike.junk.46@att.net]

I'm having no luck sending email through frontier.com.
Their setup page says to use port 465 but that causes their server to disconnect immediately.
Using port 587 I get a lot further but it dies on
'SMTP>> MAIL FROM:<> SIZE=3093
        <>: Sender address rejected: Access denied'
Though I've played with lots of things I'm pretty sure the only thing that's changed from when all was working well with SuddenLink.net is:
 /etc/exim4/passwd.client:
    smtp.frontier.com:mikemcclain.46@frontier.com:myPassWd
/etc/exim4/update-exim4.conf.conf:
    dc_smarthost='smtp.frontier.com::587'
and /etc/email-addresses:
    root: mikemcclain.46@frontier.com
    mike: mikemcclain.46@frontier.com

If anyone has exim4 working with frontier.com or simply has suggestions related to what I'm missing I'd love to hear it as I've been chasing this for a couple of weeks now.
Thanks,
Mike