diff --git a/images/kiwix/run.sh b/images/kiwix/run.sh
index 0654c9c..61c62ed 100755
--- a/images/kiwix/run.sh
+++ b/images/kiwix/run.sh
@@ -11,6 +11,7 @@ echo "[wrapper] Args: $*";
 echo ">>> Checking environment";
 if [[ -z "${NOMAD_PORT_KIWIX}" ]]; then
 	echo "Error: The environment variable NOMAD_PORT_KIWIX is not set. It must be set to the port number to listen on." >&2;
+	exit 1;
 fi
 
 echo ">>> Starting kiwix";