File Type Accept PDF fails

Hi,

I've got a form that requires the upload of a PDF that works on both a Local and Staging server, but not on the Live server.

<perch:input type="file" id="cv" accept="pdf"  required="true" />

The problem with the Live Server is that when uploading a PDF it returns the file type error (but Only on the Live server, not Local or Staging).

        <perch:error for="cv" type="filetype">
          <p class="error">File must be a PDF document.</p>
        </perch:error>   

The code is exactly the same across servers, the default filetypes.ini is included i.e.

Any ideas on what to look for or change on the Live Server settings? Thanks!