Buttons in mobile version do not work

Question

Good morning guys, I have a finished site, it is working perfectly on the desktop, but in mobile mode, all buttons do not work, the side menu however is perfect, only the buttons of the pages that do not work. I’m using these buttons controls:

<a href="research.jsp" class="btn btn-md btn-primary">MORE</a>

CSS:

btn-primary {
  color: #ffffff;
  background-color: #3314a8;
  border-color: #250d7e;
}
.btn-primary:hover {
  color: #ffffff;
  background-color: #eb3865;
  border-color: #df0038;
  -moz-transition: 0.3s all ease;
  -o-transition: 0.3s all ease;
  -webkit-transition: 0.3s all ease;
  transition: 0.3s all ease;
}
.btn-primary:active {
  background-color: #000000;
  border-color: #000000;
}