diff --git a/app/templates/views/send-test.html b/app/templates/views/send-test.html
index be3b32a9a..fd5eb63db 100644
--- a/app/templates/views/send-test.html
+++ b/app/templates/views/send-test.html
@@ -38,7 +38,7 @@
   ) %}
     <div class="grid-row">
       <div class="grid-col-12 {% if form.placeholder_value.label.text == 'phone number' %}extra-tracking{% endif %}">
-        {{ form.placeholder_value(param_extensions={"id": "phone-number"}) }}
+        {{ form.placeholder_value(param_extensions={"classes": "", "id": "phone-number"}) }}
       </div>
       {% if skip_link or link_to_upload %}
         <div class="grid-col-12 margin-top-1">