diff --git a/Development/GXDLMSServer.cs b/Development/GXDLMSServer.cs
index ebc5f9dd..122babf0 100644
--- a/Development/GXDLMSServer.cs
+++ b/Development/GXDLMSServer.cs
@@ -1904,6 +1904,11 @@ private void HandleAarqRequest(GXByteBuffer data, GXDLMSConnectionEventArgs conn
                         error.SetUInt8(ServiceError.Initiate);
                         error.SetUInt8(Initiate.IncompatibleConformance);
                     }
+                    //If PDU is 0 we set to max allowed.
+                    else if (Settings.MaxPduSize == 0)
+                    {
+                        Settings.MaxPduSize = 65535;
+                    }
                     //If PDU is too low.
                     else if (Settings.MaxPduSize < 64)
                     {
@@ -2386,4 +2391,4 @@ internal void InvokePostRead(ValueEventArgs[] args)
             PostRead(args);
         }
     }
-}
\ No newline at end of file
+}