diff --git a/src/main/java/org/mskcc/smile/service/impl/RequestFilterMsgHandlingServiceIml.java b/src/main/java/org/mskcc/smile/service/impl/RequestFilterMsgHandlingServiceIml.java
index b93b3b2..1531999 100644
--- a/src/main/java/org/mskcc/smile/service/impl/RequestFilterMsgHandlingServiceIml.java
+++ b/src/main/java/org/mskcc/smile/service/impl/RequestFilterMsgHandlingServiceIml.java
@@ -106,7 +106,9 @@ public void run() {
                         // data dog log message
                         String ddogLogMessage = validRequestChecker.generateValidationReport(
                                 requestJson, filteredRequestJson);
-                        LOG.info(ddogLogMessage);
+                        if (ddogLogMessage != null) {
+                            LOG.info(ddogLogMessage);
+                        }
                     }
                     if (interrupted && requestFilterQueue.isEmpty()) {
                         break;