I played with this some more. It turns out they don't care what is in the To: and From: fields in the header... but the following lines must be of the form <email> :
curl_easy_setopt(curl, CURLOPT_MAIL_FROM, RCPT_FROM);
recipients = curl_slist_append(recipients, RCPT_TO);
This makes more sense.
Cheers,
Sean
-------------------------------------------------------------------
Unsubscribe: https://cool.haxx.se/list/listinfo/curl-library
Etiquette: https://curl.haxx.se/mail/etiquette.html
