diff --git a/src/main/java/io/redlink/more/data/controller/ExternalDataApiV1Controller.java b/src/main/java/io/redlink/more/data/controller/ExternalDataApiV1Controller.java
index 1d0ae97..ad97620 100644
--- a/src/main/java/io/redlink/more/data/controller/ExternalDataApiV1Controller.java
+++ b/src/main/java/io/redlink/more/data/controller/ExternalDataApiV1Controller.java
@@ -69,7 +69,7 @@ public ResponseEntity<Void> storeExternalBulk(String moreApiToken, EndpointDataB
 
             endpointDataBulkDTO.getDataPoints().stream()
                 .map(ExternalDataDTO::getTimestamp)
-                .map(timestamp -> timestamp.isBefore(interval.getStart()) || timestamp.isAfter(interval.getEnd()))
+                .map(timestamp -> !(timestamp.isBefore(interval.getStart()) || timestamp.isAfter(interval.getEnd())))
                 .filter(v -> v)
                 .findFirst()
                 .orElseThrow(BadRequestException::TimeFrame);