Myujth

I am sending all my WordPress emails using Mailgun SMTP.

Other emails from WordPress arrive to the inbox fine, but I have just created a new function to automatically generate an email when a post is published and it always gets caught by the spam filter.

Can you see why?

Maybe something to do with my headers config?

I have tried sending with and without the attachment, it makes no difference.

add_action( 'publish_post', 'notify_on_publish' );
function notify_on_publish( $post_id ) 

 global $post;

 $from_name = get_bloginfo( 'name' );
 $from_email = get_bloginfo( 'admin_email' );
 $to_email = get_post_meta( $post_id, 'contact_email', true );
 $attachment = get_post_meta( $post_id, 'post_image', true );

 $headers = "From: '$from_name' <$from_email> rn Content-type: text/html; charset=" . get_option('blog_charset') . "rn";
 $subject = "This is a test subject";
 $message = "<p>This is some test body text</p>";
 $attachment_url = $attachment['guid'];

 wp_mail( $to_email, $subject, $message, $headers, $attachment_url );

Could you please share the full message header of the email which is received in your Gmail?

You will get this by clicking on SHOW ORIGINAL in Gmail.