diff --git a/.readthedocs.yml b/.readthedocs.yml
index 917704b..c05482e 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -10,3 +10,7 @@ python:
   install:
     - requirements: ci/rtd-requirements.txt
     - path: .
+
+sphinx:
+  fail_on_warning: true
+  configuration: docs/source/conf.py
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 5b736c1..d7f339e 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -87,7 +87,7 @@
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
@@ -117,7 +117,6 @@
 import sphinx_rtd_theme
 
 html_theme = "sphinx_rtd_theme"
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the