diff --git a/modoboa/templates/404.html b/modoboa/templates/404.html
index d798468b6..78aef1dae 100644
--- a/modoboa/templates/404.html
+++ b/modoboa/templates/404.html
@@ -1,4 +1,4 @@
 {% extends "layout_simple.html" %}{% load i18n %}
 {% block content %}
-<p class="well">{% trans "The requested page does not exist." %}</p>
+<div class="alert alert-info">{% trans "The requested page does not exist." %}</div>
 {% endblock %}
diff --git a/modoboa/templates/500.html b/modoboa/templates/500.html
index afff91d1b..084fb687b 100644
--- a/modoboa/templates/500.html
+++ b/modoboa/templates/500.html
@@ -1,4 +1,4 @@
 {% extends "layout_simple.html" %}{% load i18n %}
 {% block content %}
-<p class="well">{% trans "An internal error occured." %}</p>
+<div class="alert alert-error">{% trans "An internal error occured." %}</div>
 {% endblock %}