Hi,

I can establish a connection from UA expert to the node-red OPC UA server. 

The first time I tried to establish the connection the UA Expert made 

opc.tcp://hostname: iot2000: Host name lookup failure:53880/UA/SimpleNodeRedServer

 out of  

opc.tcp://192.168.200.1:53880/UA/SimpleNodeRedServer

 So I could not connect, because of this change (makes sense). 

After going to the connection settings and changing it back to the IP address, I got this message:  

There was no exact match for the specified URL in the servers's endpoint, using the first server certifcate found for connecting.

 After clicking OK in this message box, I had to trust the certificate and the connection was established! 

Hello,

I think its the combination of the example server nodes and the hostname "iot2000", which are causing this issue.

With the node-red-contrib-iiot-opcua package the .NET Client from Unified Automation is also unable to resolve proper Endpoint-URLs:

And in UaExpert you can see that the example server is using the hostname in the Endpoint-Url:

If you try this example server you will see that it works fine with the .NET Client, even though we use the same node-opcua package as node-red-contrib-opcua and node-red-contrib-iiot-opcua do:

This is because we picked an alternate hostname when initializing the OPC UA Server in app.js:

So my suggestion would be to implement the OPC UA Server in native NodeJS just like we did in our example. You can also find a tutorial here

But generally speaking I would not recommend using these NodeJS-OPC UA servers in industrial applications as we have experienced several crashes in the past.

Kind regards!