diff --git a/readthedocs/proxito/views/serve.py b/readthedocs/proxito/views/serve.py
index c14a5b0b400..e73fca8d93f 100644
--- a/readthedocs/proxito/views/serve.py
+++ b/readthedocs/proxito/views/serve.py
@@ -848,7 +848,7 @@ def get_using_unresolver(self, request, path):
         if response:
             return response
 
-        # No custom 404 page, use our contextualized 404 response
+        # Don't use the custom 404 page, use our general contextualized 404 response
         # Several additional context variables can be added if the templates
         # or other error handling is developed (version, language, filename).
         raise contextualized_404_class(
diff --git a/readthedocs/templates/errors/404/no_language.html b/readthedocs/templates/errors/404/no_language.html
index 03d8c79670c..015a9397d5d 100644
--- a/readthedocs/templates/errors/404/no_language.html
+++ b/readthedocs/templates/errors/404/no_language.html
@@ -5,6 +5,6 @@
 
 {% block 404_error_message %}
   {% include "errors/404/include_error_message.html" %}
-  {% include "errors/404/include_search.html" %}
+  {% include "errors/404/include_search.html" with search_project=project.slug %}
   {% include "errors/404/include_tips.html" %}
 {% endblock %}
diff --git a/readthedocs/templates/errors/404/no_subproject.html b/readthedocs/templates/errors/404/no_subproject.html
index c6635f691a7..6958f403e13 100644
--- a/readthedocs/templates/errors/404/no_subproject.html
+++ b/readthedocs/templates/errors/404/no_subproject.html
@@ -5,6 +5,6 @@
 
 {% block 404_error_message %}
   {% include "errors/404/include_error_message.html" %}
-  {% include "errors/404/include_search.html" %}
+  {% include "errors/404/include_search.html" with search_project=project.slug %}
   {% include "errors/404/include_tips.html" %}
 {% endblock %}
diff --git a/readthedocs/templates/errors/404/no_version.html b/readthedocs/templates/errors/404/no_version.html
index 4870c6daa09..3e4d62c939d 100644
--- a/readthedocs/templates/errors/404/no_version.html
+++ b/readthedocs/templates/errors/404/no_version.html
@@ -5,6 +5,6 @@
 
 {% block 404_error_message %}
   {% include "errors/404/include_error_message.html" %}
-  {% include "errors/404/include_search.html" %}
+  {% include "errors/404/include_search.html" with search_project=project.slug %}
   {% include "errors/404/include_tips.html" %}
 {% endblock %}