diff --git a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Adapters/RealMxGatewayClient.cs b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Adapters/RealMxGatewayClient.cs
index 8435d1d6..ac7c7086 100644
--- a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Adapters/RealMxGatewayClient.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Adapters/RealMxGatewayClient.cs
@@ -435,6 +435,21 @@ public sealed class RealMxGatewayClient : IMxGatewayClient
         string s => s.ToMxValue(),
         DateTimeOffset dto => dto.ToMxValue(),
         DateTime dt => dt.ToMxValue(),
+        // List/array attribute values. The InstanceActor decodes a canonical JSON
+        // List attribute into a typed List<T> (AttributeValueCodec produces
+        // List<string|int|float|double|bool|DateTime>) before the write so the DCL
+        // can push a real MXAccess array. Map each to the client's typed array
+        // encoder. Without these a List<T> would fall through to Convert.ToString
+        // and write a garbage scalar string to an array node — which the gateway's
+        // COM write then rejects/blocks (the array-write hang).
+        IReadOnlyList<bool> lb => lb.ToMxValue(),
+        IReadOnlyList<int> li => li.ToMxValue(),
+        IReadOnlyList<long> ll => ll.ToMxValue(),
+        IReadOnlyList<float> lf => lf.ToMxValue(),
+        IReadOnlyList<double> ld => ld.ToMxValue(),
+        IReadOnlyList<string> ls => ls.ToMxValue(),
+        IReadOnlyList<DateTimeOffset> ldto => ldto.ToMxValue(),
+        IReadOnlyList<DateTime> ldt => ldt.Select(d => (DateTimeOffset)d).ToList().ToMxValue(),
         // Fall back to invariant string for any other CLR type.
         _ => Convert.ToString(value, CultureInfo.InvariantCulture)!.ToMxValue(),
     };