I have a simple form -- just 2 fields, Name and Email address. When I enter a yahoo or hotmail email address in the form, no email is sent even though the message for successful sending appears after I hit Send. Email is sent successfully when the email address entered in the form is gmail or any private domain email address.
I'm using WP-Mail-SMTP plugin also... The "To:" in the Mail section of the Contact form setup is to a private email and the same email is in the From of the WP-Mail-SMTP setup....not sure it matters....