What version of email scripts are you using? You can remove the redirect and dump the mail object on the page after sending to see if there are any errors or issues in the email body. What email address are you using for the To and From? There are so many things it could be.
You could try a simple test script to see if emails send at all from your site. You can find some sample scripts here: https://www.php.net/manual/en/function.mail.php