Can connect client, but no items visible

[djimmo]

I installed the OPC Server and I am trying to view the items in Matrikon OPC Explorer. I can see the server and can successfully connect to it, however no items are visible. The logging from the OPC Server shows the following:

18-Mar-19 13:35:44 > Running OPC Server from C:\Users\Djim\Downloads\ArduinoOPCServer.exe
18-Mar-19 13:35:44 > Waiting for OPC clients to connect....
18-Mar-19 13:36:21 > Connected client
18-Mar-19 13:36:21 > Trying to open COM5 port
18-Mar-19 13:36:21 > COM5 port open
18-Mar-19 13:36:21 > Asking for available OPCItems from ArduinoSerial0
18-Mar-19 13:36:21 > Frame:

On the last line it should send an overview with available fields, as I concluded from some of the video tutorials. Unfortunately it's blank... Any help would be greatly appreciated

regards,
Djim