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Read service is denied for client

22 May 2023 18:36 #11747 by support
Oh, I see. Thank you for explanation.

As you probably understand, the error is actually not coming from the client application at all. It is being logged on the OPC UA server side. "OpcLabs.EasyOpc.UA.Implementations.NetSdk.EasyUASession;5.53.405.1@PC363/13432:1;2891" is an OPC UA session name that we pass from the client to the server, and the server is including it in the event so that it identifies the client that it relates to.

But I do not know what the error means and what causes it. You need to ask the server vendor. It is somewhat weird that it has the string "user , item" at the end - does that indicate no user, and perhaps no valid node Id? But again, it's reported by the server, and it is server-specific, so it's their turn to explain it.

What is not clear to me is whether you are actually having a problem (the application does not work as expected), or whether the application appears to work well, and you are just trying to figure what the errors in the event log mean.

Note: The server may (and usually will ) indicate a problem during reading by setting a "Bad" status status in the DataValue sent to client. In such case, the indication of it will be inside the UAAttributeData that you get from the Read call, but there will be no exception thrown. Are you checking the status of UAAttributeData?

Best regards

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22 May 2023 12:42 #11746 by mpedro
Hello, first of all thank you for your reply.
Let me explain: it ins't an exact expection captured by the program, it is an error logged under event viewer of the windows. As in the program I have some try-cathch blocs i don't see any exception. Furthermore the program runs as a service so the user don't realize it's running.

What the error event tells is:

Logged Date: 09:35:06 Tuesday, May 16, 2023
Location: PC363 Provider: FactoryTalk Linx Gateway UA

Read service is denied for client <OpcLabs.EasyOpc.UA.Implementations.NetSdk.EasyUASession;5.53.405.1@PC363/13432:1;2891,>, user , item
Please tell me if more information is needed. Thank you very much.

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22 May 2023 12:36 #11744 by support

can you please provide more information about the exception? I think what you have written is neither precise nor complete. Use Copy/Paste.

I need:
- The precise full text of the exception message
- The exception call stack
- If there is an inner exception (.InnerException property), then its type, its precise full text, and its call stack, and so on, recursively.

Thank you
The following user(s) said Thank You: mpedro

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22 May 2023 09:57 #11743 by mpedro
i'm reading a Rockwell PLC using OpcLabs and a windows console application developed in C#. Since 2017 i'm using easyOPC libraries and so far I didn't have any problems. the issue appears when using OPC UA and every 1-2 weeks because I get the following error:
-Read service is denied for client <Opclabs.EasyOpc.UA.implementations.netsdk.easyUAsession...

I have an OPC server configurated with anonymous authentication and security none. What it makes nonsense for me is the error telling read is denied...

how i read:
UAAttributeData v = new UAAttributeData();
v= _servidor.Read(serverString, tagName);

Is it a bug or a wrong configuration?

Thanks for the help

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