I have the problem that when receiving the email from the contact form, the emails are always grouped. This causes all the emails to be deleted when the user deletes an email. This is an Outlook and user problem. However, I would like to set the email to be unique in the communication. So subject should be the subject field and sender should always be the person who used the form and my server email.
What can I do to solve the problem on the server side.
Making the subject field come from the web form poses some security challenges, but we’ll look into adding it.
It’s not possible to set the site visitor email as the “From” email header, because spam filters will then delete the email.
Technically this is how the anti-spam provisions work:
the site visitor enters their address, say user@gmail.com
if the web form were to put that in the From: address, you’d have a mail header like From: user@gmail.com
the spam filter looks at the email From: header, and then looks at the gmail.com record for the “Sender Policy Framework” (SPF), this is essentially a list of servers allowed to send email on behalf of the gmail.com domain
your web server is clearly not going to be on that list