Tal vez importó la biblioteca jQuery dos veces,

[jdelrosario]

Estos son todos los js:
<!--================================================== -->
<script src="contactme/js/jquery-3.3.1.min.js"></script>
<!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->

<!-- START js copy section -->

<script src="contactme/js/weakmap-polyfill.min.js"></script>
<script src="contactme/js/formdata.min.js"></script>
<script src="contactme/js/bootstrap-datepicker.min.js"></script>
<script src="contactme/js/bootstrap-datepicker-lang/en.js"></script>
<script src="contactme/js/jquery.timepicker.min.js"></script>
<script src="contactme/js/select2.full.min.js"></script>
<script src="contactme/js/select2-lang/en.js"></script>
<!--[if lt IE 9]><script src="contactme/js/EQCSS-polyfills-1.7.0.min.js"></script><![endif]-->
<script src="contactme/js/EQCSS-1.7.0.min.js"></script>
<script src="contactme/js/contactme-config.js"></script>
<script src="contactme/js/contactme.js"></script>

<!-- END js copy section -->
<!-- Vendor JS Files -->

<script src="assets/vendor/aos/aos.js"></script>
<script src="assets/vendor/bootstrap/js/bootstrap.bundle.min.js"></script>
<script src="assets/vendor/glightbox/js/glightbox.min.js"></script>
<script src="assets/vendor/isotope-layout/isotope.pkgd.min.js"></script>

<script src="assets/vendor/purecounter/purecounter.js"></script>
<script src="assets/vendor/swiper/swiper-bundle.min.js"></script>

<!-- Template Main JS File -->
<script src="assets/js/main.js"></script>

Son inherentes al diseño de la página en si, mas los que se conectan con el envío a proceso del formulario.
Muchas gracias por la atención.
Jdel