fatal contact form miss-coding in vb3 (sending domain)

[Ghostt]

Hello.
i want to send contact form emails through mandrill smtp service.
but there are problems with sending domain.

here is what they wrote me:

Thanks for reaching out. To clarify, any domain used in the "from" address of an email sent through your account will be added to the "sending domains" page. For contact forms, we would suggest programming the form to use your own address as the "From" address, and?if needed?your user's address as the reply-to address. This would be accomplished using the headers array of your API call, formatted as:

"headers": {
"Reply-To": "message.reply@example.com"
},

That will allow you to send from a domain with DKIM/SPF authentication set up, which can help improve your deliverability.

Please let us know if you have any other questions, and we'd be happy to assist.

The Mandrill Crew

any idea how to fix?