display-form-errors.html

{% if form.errors %}
  <div class="alert alert-danger">
    {% for field in form %}
      {% if field.errors %}
      <div><strong>{{ field.label }}</strong>: {{ field.errors|striptags }}</div>
      {% endif %}
    {% endfor %}
    {% for error in form.non_field_errors %}
      <div>{{ error|striptags }}</div>
    {% endfor %}
  </div>
{% endif %}