diff --git a/persistence-service-v1/persistence-service-external-api-impl-v1/src/main/java/com/iqser/red/persistence/service/v1/external/api/impl/controller/RulesController.java b/persistence-service-v1/persistence-service-external-api-impl-v1/src/main/java/com/iqser/red/persistence/service/v1/external/api/impl/controller/RulesController.java
index 5ab60c1ac..c2bbc3ffa 100644
--- a/persistence-service-v1/persistence-service-external-api-impl-v1/src/main/java/com/iqser/red/persistence/service/v1/external/api/impl/controller/RulesController.java
+++ b/persistence-service-v1/persistence-service-external-api-impl-v1/src/main/java/com/iqser/red/persistence/service/v1/external/api/impl/controller/RulesController.java
@@ -75,16 +75,27 @@ public class RulesController implements RulesResource {
         if (ruleEntityOptional.isPresent()) {
             RulesUpdateRequest rulesUpdateRequest = new RulesUpdateRequest(ruleEntityOptional.get().getValue(), rules.getRules());
             try {
-                ResponseEntity mergedRules = ruleBuilderClient.mergeUserUpdateRules(rulesUpdateRequest);
+                ResponseEntity<RulesUploadResponse> mergedRules = ruleBuilderClient.mergeUserUpdateRules(rulesUpdateRequest);
+
+                if (mergedRules == null || mergedRules.getBody() == null) {
+                    throw new BadRequestException("Failed to merge rules - received null response from service");
+                }
+
                 if (mergedRules.getStatusCode().equals(HttpStatus.UNPROCESSABLE_ENTITY)) {
-                    DroolsValidationResponse mergedRulesValidationResponse = ((RulesUploadResponse) mergedRules.getBody()).getDroolsValidationResponse();
+                    DroolsValidationResponse mergedRulesValidationResponse = mergedRules.getBody().getDroolsValidationResponse();
                     return new ResponseEntity<>(mergedRulesValidationResponse, !rules.isDryRun() ? HttpStatus.UNPROCESSABLE_ENTITY : HttpStatus.OK);
                 }
-                mergedRulesString = ((RulesUploadResponse) mergedRules.getBody()).getRules();
+
+                mergedRulesString = mergedRules.getBody().getRules();
+                if (mergedRulesString == null) {
+                    throw new BadRequestException("Failed to merge rules - merged result is null");
+                }
+
             } catch (FeignException e) {
                 if (e.status() == HttpStatus.BAD_REQUEST.value()) {
                     throw new BadRequestException("The provided rule file is not a valid drools rule file!");
                 }
+                throw new BadRequestException("Failed to merge rules: " + e.getMessage());
             }
         }
         if (!rules.isDryRun()) {