diff --git a/docs/root/Makefile b/docs/root/Makefile
index 77a0810b..578ec7d6 100644
--- a/docs/root/Makefile
+++ b/docs/root/Makefile
@@ -2,7 +2,7 @@
 #
 
 # You can set these variables from the command line.
-SPHINXOPTS    =
+SPHINXOPTS    = -W
 SPHINXBUILD   = sphinx-build
 PAPER         =
 BUILDDIR      = build
diff --git a/docs/server/Makefile b/docs/server/Makefile
index 38b7ed1d..649738aa 100644
--- a/docs/server/Makefile
+++ b/docs/server/Makefile
@@ -2,7 +2,7 @@
 #
 
 # You can set these variables from the command line.
-SPHINXOPTS    =
+SPHINXOPTS    = -W
 SPHINXBUILD   = sphinx-build
 PAPER         =
 BUILDDIR      = build