Is it possible that this tags are blocked to use them outside OPC server?
May be, but I don’t think so.
Matrikon also provides OPC Explorer. Try to use it for get data of that tags. Does it work?
I can connect to your PC remotely to do more diagnostic, however this is a commercial service and I’m not sure that I reach success in fixing this problem.
I tried restarting communicator and also setting the tag´s names from administrator but still not work.
Please provide communication line log.