I have an internet application that requires my users send invoices to their clients. We use MailEnable and send the invoices TO the client email FROM our user's email address using our IP. Lately there has been lots of delivery failures due to "policy reasons" or DMARC issues.
This makes sense that most of the public addresses (Yahoo, AOL, Gmail, etc.) have restrictions in place to safeguard against spoofing, however this is now causing us major headaches and our users are getting frustrated because their emails not getting delivered.
I have tried explaining the WHY they are not delivered and that the sending domain's IP doesn't match the From address domain IP, but it goes right over my user's heads and they keep blaming our app for the error.
What solutions are available for me to get my users' invoices out to their clients through my application? It's a classic .asp application residing on a MS Windows 2008 R2 Standard server.
TIA - Any and All suggestions welcome!