I agree that there is a similarity to the issue you have referenced.

Can you obtain the logs (including Wireshark), as you have done for that other issue? (I suppose that your app can log every notification from QuickOPC, so that I can tell when they have come - and more importantly, when they haven't).

Thank you

Thank you. I suggest that this issue it put to hold until www.opclabs.com/forum/ua-connections/2616-unable-to-reconnect-to-opc-server#7200 is resolved, as there is a (small) possibility that they are related.

In the meantime, can you please clarify something. It has to do with the usage of the term "subscription" in your original post. Unfortunately, the term "subscription" is overloaded, so it can mean multiple things, and it is important for the analysis to understand what is it that you had in mind.

Let me explain:
The underlying software uses following model for OPC UA communication:
- An engine: maintains client Sessions to OPC UA servers.
- A (client) session: Basically, a communication channel to a single server endpoint. Allows to call UA services such as Read, Write, Browse, etc. Maintains subscriptions.
- A (client) subscription: Lives on a session. Maintains Monitored Items, and receives/manages the data updates. All monitored items under one subscription share some common characteristics (the update rate, mainly).
- A monitored item. Part of a subscription - the individual piece of data being subscribed to.

So, we have one meaning of "subscription" - above. But this model is more or less hidden from you, and when you use the EasyUAClient, you make calls such as SubscribeDataChange, which already encompasses all of the above (creates these objects as needed) - and, here we have the second meaning of the term "subscription".

When you wrote "If we add a new subscription to the same server, it seams like we do not get any callbacks on the new subscription either ", did the newly added item have the same subscription parameters (update rate, mainly) as any existing ones on that server, or did it use the same parameters? This gets to the distinction between the first and second meaning of the term. This is relevant, because with different parameters, EasyUAClient will create a new client subscription, but with the same parameters, it will just add a monitored item to the same subscription. The resulting communication and general behavior is then different. For example, it would be unlikely that if the "old" and "new" item were on the same client subscription, that one of them would work and the other not - if so, I would prefer to see the Wireshark logs and see if it might be the server to blame. And there are other differences, too.

Regards

Hello.

Before I go further on this, I want to check one thing. When you observe these issue, are you sure there there is no "INTERNAL ERROR" reported through the LogEntry, whatsoever, during the run of the process? Because, if it were, it has to be resolved first, as it might be causing any kind of issue later on.

Regards