The most common form problem.
THE USUAL CAUSE
The form sends from an address that is not yours, or from your domain without proper authentication.
Receiving servers treat it as forged and reject or filter it.
THE SPECIFIC PROBLEM
Many form plugins send with the visitor's address as the sender.
Your server is not authorised to send as their domain, so it fails SPF and is rejected.
THE FIX
Send from an address on your own domain, such as [email protected].
Put the visitor's address in the reply-to field instead.
That way replying still reaches them, and delivery succeeds.
WHAT ELSE TO CHECK
SPF and DKIM configured for your domain cPanel Email Deliverability showing no problems The recipient address actually exists
USING SMTP
Sending through an authenticated mail account rather than the server's default improves delivery substantially.
An SMTP plugin configures this.
HOW TO TEST
Submit the form and check the recipient inbox and spam folder.
Test to a major provider, not only your own domain.
