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Failed to create session channel to server
September 8, 2016
9:15, EEST
Heikki Tahvanainen
Forum Posts: 402
Member Since:
April 17, 2013
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I guess that new specification versions almost inevitable cause some amount of interop problems. I’ll be happy to hear more about your client certificate issue although it initially sounds like a server application issue. The CreateSession service specification says that “If the securityPolicyUri is None, the Server shall ignore the (client) ApplicationInstanceCertificate.”

The original issue in this forum thread was that the client side Java stack still expected that the server would send serverCertificate in all of the serverEndpoints returned in the CreateSession response. This functionality was changed in OPC UA specification version 1.02. The current specification tells that the server must send the (server) ApplicationInstanceCertificate in the createSession response but not in the individual EndpointDescriptions. It seems that somehow this issue has not been detected before this, probably because most of the other stacks have kept backwards compatibility with version 1.01 spec.

March 1, 2023
12:27, EET
Forum Posts: 34
Member Since:
February 14, 2020
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we use Version 4.2.0-955 of Java SDK. unfortunately I can’t update it. It has to stay with the version.
We have the same problem:

[24.02. 17:26:20,755][PublishTask-com.prosysopc.ua.client.UaClient@6ae2f049][INFO][OPCUA.Service] >Server DMC_1150 changed the State from “Running” to “CommunicationFault”client session name: 107f9b28-3da9-4e49-b9e1-abe141da180c-6EDD694ATimer triggered for method configuration: ServerMonitoring_ServerMonitoringreading values from server [variable name, value]Server DMC_1150 changed the State from “CommunicationFault” to “Unknown”client session name: a9b31554-9ea9-4b7b-9a63-4eb459c4be3a-78EB9459ServerStateError: Bad_SessionNotActivated (0x80270000) “The session cannot be used because ActivateSession has not been called.”Server DMC_1150 changed the State from “CommunicationFault” to “Unknown”client session name: 7e90ddf0-ced0-4874-8051-bd7114f4631c-6821ED34ServerStateError: Bad_SessionNotActivated (0x80270000) “The session cannot be used because ActivateSession has not been called.”Server DMC_1150 changed the State from “CommunicationFault” to “Unknown”<

Security Policy: None
Message Security Mode: None
do i need to change it?

How is a possible workaround for the client side ?
Must i set the parameter “ValidateDiscoveredEndpoints” to false?

Thanks you in advance.

March 1, 2023
14:10, EET
Bjarne Boström
Forum Posts: 986
Member Since:
April 3, 2012
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It is impossible to say based on your log alone that has it anything to do with the problems of this thread. You can try to set the flag as false, but most likely since the log pasted doesn’t show anything related to the endpoints it most likely wont help. Generally speaking, connections and sessions can fail in innumerable ways, also the thread was like 6.5 years ago, which is a forever in OPC UA timeframes.

Generally speaking OPC UA basically in practice requires continuous updates to the SDKs to achieve and retain interoperability (this also applies to the server here, is it running the latest version of everything?). Can you test with https://www.prosysopc.com/products/opc-ua-browser/? But realistically you should “fix” the ability to update the SDK. If you are not able to update or at least test with the latest SDK, please contact sales@prosysopc.com.

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