php电子邮件功能不适用于.org电子邮件

所以我试图发送一封电子邮件，通知办公室管理员何时通过表格提交了电子邮件。当我使用以".com"结尾的电子邮件时，一切都没有问题。然而，当我尝试使用以".org"结尾的邮件时，

$first_name = $_POST['first_name'];
$last_name = $_POST['last_name'];
$email_address = $_POST['email_address'];
$message = $_POST['message'];
if(isset($_POST['submit'])){
$to = "officeadmin@example.org"; // Office Admin Email
$from = $email_address; // User's Email
$subject = "Form Submission";
$content_admin = $first_name . " " . $last_name . " wrote the following:" . "'n'n" . $message;
$content_user = "Thanks again for contacting us. A dedicated staff member will contact you as soon as possible. Your message was: 'n'n" . $message;
$headers_admin = "From:" . $from;
$headers_user = "From: Example Office";
mail($to,$subject,$content_admin,$headers_admin); //Notification email for admin
mail($from,'Thanks for contacting us',$content_user, $headers_user); //Copy of email sent to user
header('Location: contact_form_success.html'); //Redirect here after submit is clicked
}