Message "301 Moved Permanently" began to appear suddenly

I have two applications that worked perfectly, but without any changes to the code, they do not work anymore.

On the one hand, an application with a JSP doing a POST call and passing two hidden parameters:

<li>
 <form name="login" method="post" action="http://dominio.com/aplicacao/chamadaApp">
  <input type="hidden" name="param1" value="conteudo1">
  <input type="hidden" name="param2" value="conteudo2">
  <A href="javascript:login()" class="classe1"></A>
  <script type="text/javascript">
   function login()
   {
    document.login.submit();
   }
  </script>
 </form>
</li>

On the other hand, another SpringMVC application with the following code snippet, receiving the above request:

@RequestMapping(value = "/chamadaApp", method = RequestMethod.POST)
    public ModelAndView login(
      @RequestParam(value = "param1", required = false) String param1,
      @RequestParam(value = "param2", required = false) String param2,
      WebRequest request) {
 //código
}

It worked perfectly, but suddenly the SpringMVC application started to return the HTTP Status 405 - Request method 'GET' not supported error. This makes no sense since both the HTML makes a POST call and the application also expects to receive a POST call.

Investigating a little more, I discovered with FIREBUG that when performing the APp call, before showing the above error, the status is returned: 301 Moved Permanently , which made me suspect some problem below, but I have no idea what it can be.

Does anyone know what this error means and how to solve it?