Unable update PLC tag value using Linx OPC server

PLC :- Allen-Bradley ,
App :- Linx OPC server
Language :- C#.Net

Unable to update the PLC value through a Linx OPC server using "groupStateWrite/groupWrite", I can read the data from AB PLC but sending value "(write item)" is not working.

server = new Opc.Da.Server(fact, null);
server.Url = new Opc.URL("opcda://localhost/RSLinx OPC Server");
server.Connect();

//READ GROUP SUBSCRIPTION
groupState = new Opc.Da.SubscriptionState();
groupState.Name = "New2";
groupState.UpdateRate = 1000;
groupState.Active = true;

//READ GROUP CREATION
groupRead = (Opc.Da.Subscription)server.CreateSubscription(groupState);
Opc.Da.Item[] items = new Opc.Da.Item[1];
........Read is working

//WRITE ITEM
SubscriptionState groupStateWrite = new Opc.Da.SubscriptionState();
groupStateWrite = new Opc.Da.SubscriptionState();
groupStateWrite.Name = "GroupWrite";
groupStateWrite.Active = false; ----->(either "true" or "false" is not working)
groupWrite = (Opc.Da.Subscription)server.CreateSubscription(groupStateWrite);

//CREATE THE ITEM TO WRITE
Opc.Da.Item[] itemtoadd = new Opc.Da.Item[1];
itemtoadd[0] = new Opc.Da.Item();
itemtoadd[0].ItemName = "[PLC]REPORT[0].Trigger";

//CREATE THE ITEM THAT CONTAINS THE VALUE TO WRITE
Opc.Da.ItemValue[] writevalues = new Opc.Da.ItemValue[1];
writevalues[0] = new Opc.Da.ItemValue(itemtoadd[0]);

groupWrite.AddItems(itemtoadd);
writevalues[0].Value = 0; -->I need to send or update the value from 1 to 0
groupWrite.Write(writevalues);
 
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