diff --git a/src/ZB.MOM.WW.MxGateway.Worker/MxAccess/AlarmAckWriter.cs b/src/ZB.MOM.WW.MxGateway.Worker/MxAccess/AlarmAckWriter.cs
index 87a20b5..6f61402 100644
--- a/src/ZB.MOM.WW.MxGateway.Worker/MxAccess/AlarmAckWriter.cs
+++ b/src/ZB.MOM.WW.MxGateway.Worker/MxAccess/AlarmAckWriter.cs
@@ -139,7 +139,7 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
 
         foreach (MxStatusProxy status in statuses)
         {
-            if (status.Category != MxStatusCategory.Ok)
+            if (status.Category != Contracts.Proto.MxStatusCategory.Ok)
             {
                 return AlarmAckResult.Create(
                     AlarmAckOutcome.WriteRejected,