# Opcua connection node subscription/read errors

**URL:** <https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281>\
**Category:** Ignition\
**Created:** [December 6, 2022, 1:35pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281 "2022-12-06T13:35:37Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![eric.e.fredericksen](https://avatars.discourse-cdn.com/v4/letter/e/22d042/32.png) [@eric.e.fredericksen](https://forum.inductiveautomation.com/u/eric.e.fredericksen)\
**Post date:** [December 6, 2022, 1:35pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/1 "2022-12-06T13:35:37Z")

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I am developing an opcua server in node.js and after enabling authentication I want to get the users from the serverconfiguration-\>usermanagement-\>users node. When I attempt to read or subscribe to this node I get an error: Bad("Bad\_DecodingError: Decoding halted because of invalid data in the stream.").

My question is how do I see the data in the stream?

Version: **8.1.19 (b2022072711)**

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [December 6, 2022, 3:08pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/2 "2022-12-06T15:08:14Z")

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What is the DataType of the Value of that Node?

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [December 6, 2022, 3:51pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/3 "2022-12-06T15:51:13Z")

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Ah, it's a `UserManagementDataType[]`, part of the role-based security model.

This is not a type that Ignition understands right now because it's still using OPC UA 1.03. You won't be able to decode it.

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**Author:** ![eric.e.fredericksen](https://avatars.discourse-cdn.com/v4/letter/e/22d042/32.png) [@eric.e.fredericksen](https://forum.inductiveautomation.com/u/eric.e.fredericksen)\
**Post date:** [December 6, 2022, 4:25pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/4 "2022-12-06T16:25:54Z")

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Aha, Yes we are using 1.04.4 Thank you for the quick response.

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**Author:** ![Inken\_Kestler](https://avatars.discourse-cdn.com/v4/letter/i/bcef8e/32.png) [@Inken\_Kestler](https://forum.inductiveautomation.com/u/Inken_Kestler)\
**Post date:** [June 11, 2024, 11:34am UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/5 "2024-06-11T11:34:25Z")

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Hi together,  
I'm facing similar problems. I try to read a string array with OPC-UA and receive the same error message.  
@Kevin.Herron, is Ignition still using this old version of OPC-UA ?

Inken

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<div class="post-metadata">

**Author:** ![eric.e.fredericksen](https://avatars.discourse-cdn.com/v4/letter/e/22d042/32.png) [@eric.e.fredericksen](https://forum.inductiveautomation.com/u/eric.e.fredericksen)\
**Post date:** [June 11, 2024, 1:04pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/6 "2024-06-11T13:04:27Z")

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@Inken_Kestler Ignition currently supports 1.03 and only the base types. Per @Kevin.Herron  
"Alarms and Conditions and Historical Access are not implemented at all. Only basic information modeling is done. We don't have any custom ObjectTypes, VariableTypes, or DataTypes in the address space. Everything is just regular base types."

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [June 11, 2024, 1:35pm UTC](https://forum.inductiveautomation.com/t/opcua-connection-node-subscription-read-errors/67281/7 "2024-06-11T13:35:17Z")

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It's still OPC UA 1.03, but if this is really a String array and not some other type like the original poster then fundamentally there's no reason it shouldn't be readable.

One possibility I can think of is that the String and/or array length is so large that it exceeds the negotiated message sizes between client/server.

Can you make the connection without security and get a Wireshark capture while you try to read the value?
