How to remove "Please match the requested format"

<form id="banner-message">
    <input value=""
    name="email" 
    id="inputEmail"
    class="form-control"
    placeholder="email"
    required="" 
    autofocus=""  
    oninvalid="this.setCustomValidity('Not Valid')"                                               oninput="setCustomValidity('')"
    pattern="[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,3}$">

    <button class="btn btn-lg  btn-block" type="submit">Go</button>
</form>

  <form id="banner-message">
      <input value="" 
      name="email" 
      id="inputEmail"
      class="form-control"
      placeholder="email"
      required=""
      autofocus="" 
      oninvalid="this.setCustomValidity('Not Valid')"
      onchange="try{setCustomValidity('')}catch(e){}"
      oninput="setCustomValidity(' ')"
      pattern="[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,3}$">

      <button class="btn btn-lg  btn-block" type="submit">Go</button>
    </form>