app-MAIL-temp/templates/partials/toggle_contact.html

<button
    class="btn btn-sm {% if contact.block_forward %} text-primary {% else %} text-warning {% endif %}"
    hx-post="{{ url_for('dashboard.toggle_contact', contact_id=contact.id) }}" hx-swap="outerHTML">
  {% if contact.block_forward %}
    <i class="fe fe-play-circle" data-toggle="tooltip" title="Unblock sender"></i>
  {% else %}
    <i class="fe fe-pause-circle" data-toggle="tooltip" title="Block sender"></i>
  {% endif %}
</button>

{% if toast_msg %}
  <script>
    toastr.success("{{ toast_msg }}");
  </script>
{% endif %}