Hello,

Specific advice for UaExpert is outside the scope of this forum, but as generic advice, please check that the Server is running at the target machine, that the selected port is correct and that firewall is not blocking connections to that port.

Alternatively, you can try connecting to the Server with Prosys OPC UA Browser, for which we can provide more specific support.

As another alternative, you could use Wireshark to capture traffic between UaExpert and the Server and check the logs for errors. See https://prosysopc.com/blog/opc-ua-wireshark/ for instructions on how to capture OPC UA communication with Wireshark.