Install the sphinx-notfound-page Sphinx extension

docs/conf.py

@@ -27,6 +27,7 @@ sys.path.insert(0, path.dirname(path.dirname(__file__)))
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
+    'notfound.extension',
     'scrapydocs',
     'sphinx.ext.autodoc',
     'sphinx.ext.coverage',

docs/requirements.txt

@@ -1,2 +1,3 @@
 Sphinx>=2.1
-sphinx_rtd_theme
+sphinx-notfound-page
+sphinx_rtd_theme