diff --git a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
index ae055acf..4cab373a 100644
--- a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
+++ b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
@@ -187,18 +187,18 @@ namespace AsbCloudInfrastructure.Services.Subsystems
 
         /// <inheritdoc/>
         public async Task<DatesRangeDto?> GetDateRangeOperationTimeAsync(SubsystemOperationTimeRequest request, CancellationToken token)
-        {            
+        {
             var query = BuildQuery(request);
             if (query is not null)
             {
                 var result = await query
-                .GroupBy(o => o.IdSubsystem)
-                 .Select(g => new DatesRangeDto
-                 {
-                     From = g.Min(o => o.DateStart).DateTime,
-                     To = g.Max(o => o.DateEnd).DateTime
-                 })
-                 .FirstOrDefaultAsync(token);
+                    .GroupBy(o => o.IdTelemetry)
+                    .Select(g => new DatesRangeDto
+                     {
+                         From = g.Min(o => o.DateStart).DateTime,
+                         To = g.Max(o => o.DateEnd).DateTime
+                     })
+                    .FirstOrDefaultAsync(token);
                 return result;
             }
             return null;