diff --git a/CHANGES_NEXT_RELEASE b/CHANGES_NEXT_RELEASE
index a1afb8ff7..6fec658b3 100644
--- a/CHANGES_NEXT_RELEASE
+++ b/CHANGES_NEXT_RELEASE
@@ -1,3 +1,4 @@
+- [cygnus-ngsi] Fix runtime error: check access aggregator size (#2293)
 - [cygnus-ngsi] Switch log level to CYGNUS_LOG_LEVEL env var if was provided to docker (#2286)
 - [cygnus-common][SQL] Fix expiration records tablename used by delete and select (#2265)
 - [cygnus-common][SQL] Fix expiration records select with a limit to avoid java out of memory error (#2273)
diff --git a/cygnus-ngsi/src/main/java/com/telefonica/iot/cygnus/aggregation/NGSIGenericColumnAggregator.java b/cygnus-ngsi/src/main/java/com/telefonica/iot/cygnus/aggregation/NGSIGenericColumnAggregator.java
index 06086cb70..5e75c49ea 100644
--- a/cygnus-ngsi/src/main/java/com/telefonica/iot/cygnus/aggregation/NGSIGenericColumnAggregator.java
+++ b/cygnus-ngsi/src/main/java/com/telefonica/iot/cygnus/aggregation/NGSIGenericColumnAggregator.java
@@ -98,7 +98,10 @@ public void initialize(NGSIEvent event) {
     @Override
     public void aggregate(NGSIEvent event) {
         // Number of previous values
-        int numPreviousValues = getAggregation().get(NGSIConstants.FIWARE_SERVICE_PATH).size();
+        int numPreviousValues = 0;
+        if (getAggregation().get(NGSIConstants.FIWARE_SERVICE_PATH) != null) {
+            numPreviousValues = getAggregation().get(NGSIConstants.FIWARE_SERVICE_PATH).size();
+        }
         // get the servicePath from event
         String eventServicePath = event.getServicePathForData();
         // Get the event headers