exim4 vs. frontier.com

[mike.junk.46@att.net]

I've struggled off and on for months to get outbound mail via exim4 through frontier.com with no joy.
I'm on a single user system using mutt and exim4 plus fetchmail. Inbound is no problem.
Outbound I see this in /var/log/exim4/mainlog:
    554 5.7.1 <>: Sender address rejected: Access denied
/etc/email-addresses has the proper frontier email address in it.
>From web search I created /etc/exim4/conf.d/rewrite/10_from_rewrite containing this line:
*              "$header_from:" F
This supposedly tells exim4 to set the Envelope header the same as the From header.
I think Sent = Envelope headers, admittedly not sure about that.

If there is anyone on the list who has exim4 talking to Frontier.com please help.

Thanks,
Mike