diff --git a/bin/generate-samples.sh b/bin/generate-samples.sh
index 1adcab12e5c1..197eb9183912 100755
--- a/bin/generate-samples.sh
+++ b/bin/generate-samples.sh
@@ -68,6 +68,5 @@ fi
 
 if [[ -n "$GENERATE_ERROR" ]]; then
   echo "Found exception(s) when running the generator(s) to update the samples."
-  # UNCOMMENT LATER
-  #exit 1
+  exit 1
 fi
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java
index 559417a0e78e..fdd2249c00cb 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java
@@ -696,7 +696,7 @@ protected boolean isSelfReference(String name, Schema subSchema) {
      */
     public Schema normalizeSchema(Schema schema, Set<Schema> visitedSchemas) {
         // normalize reference schema
-        if (StringUtils.isNotEmpty(schema.get$ref())) {
+        if (schema != null && StringUtils.isNotEmpty(schema.get$ref())) {
             normalizeReferenceSchema(schema);
         }