diff --git a/AsbCloudInfrastructure/Services/DetectOperations/DetectedOperationService.cs b/AsbCloudInfrastructure/Services/DetectOperations/DetectedOperationService.cs
index 6bf0cdf5..36809ec3 100644
--- a/AsbCloudInfrastructure/Services/DetectOperations/DetectedOperationService.cs
+++ b/AsbCloudInfrastructure/Services/DetectOperations/DetectedOperationService.cs
@@ -156,6 +156,7 @@ public class DetectedOperationService : IDetectedOperationService
             var detectableTelemetries = (await telemetryDataSaubService.GetByTelemetryAsync(idTelemetry, request, token))
                 .Where(t => t.BlockPosition >= 0)
                 .Select(t => t as TelemetryNewDataSaubDto)
+                .Where (t => t is not null)
                 .Select(t => new DetectableTelemetry
                 {
                     DateTime = t.DateTime,