Error Message not displaying

Hi, I am using drupal 8 and having the following code for my custom theme’s template file, ” page.twig.html “

<section{{ content_attributes.addClass(content_classes) }}>

        {# Highlighted #}
        {% if page.highlighted %}
          {% block highlighted %}
            <div class=”highlighted”>{{ page.highlighted }}  </div>
          {% endblock %}
        {% endif %}

        {# Breadcrumbs #}
        {% if breadcrumb %}
          {% block breadcrumb %}
            {{ breadcrumb }}
          {% endblock %}
        {% endif %}

        {# Action Links #}
        {% if action_links %}
          {% block action_links %}
            <ul class=”action-links”>{{ action_links }}</ul>
          {% endblock %}
        {% endif %}

        {# Help #}
        {% if page.help %}
          {% block help %}
            {{ page.help }}
          {% endblock %}
        {% endif %}

        {# Content #}
        {% block content %}
          <a id=”main-content”></a>
          {{ page.content }}
        {% endblock %}
      </section>

And i am having a custom module for a form with validation. Whenever the form is submitted with invalid enteries, the error is expected to show over there in highlighted region, as my status messages are under the block – highlighted. But it fails to show the error messages. Can anyone help me please?

Drupal version: 


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