# Invalid endpoint message when using Node-Red-contribut-opcua

**URL:** <https://discourse.nodered.org/t/invalid-endpoint-message-when-using-node-red-contribut-opcua/97449>\
**Category:** Industrial\
**Tags:** opcua\
**Created:** [6 June 2025 12:26 UTC](https://discourse.nodered.org/t/invalid-endpoint-message-when-using-node-red-contribut-opcua/97449 "2025-06-06T12:26:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![enginebeat](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/enginebeat/32/92241_2.png) [@enginebeat](https://discourse.nodered.org/u/enginebeat)\
**Post date:** [6 June 2025 12:26 UTC](https://discourse.nodered.org/t/invalid-endpoint-message-when-using-node-red-contribut-opcua/97449/1 "2025-06-06T12:26:43Z")

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Hi All,  
Trying to use Node-red-contribut-opcua, but I get the invalid endpoint message. both my Twincat and UAExpert connect no problem and also tried the palette opcua/for-node-red and that seems to work fine, so I'm at a bit of a loss, why it doesn't work.  
On Debug I get this message about certification:

> Blockquote

Error: Certificate file must exist :C:\Users\desousa\AppData\Roaming\node-opcua-default-nodejs\Config\PKI\own\certs\client\_certificate.pem

> Blockquote

I selected certification none, so I'm not sure why I get this.  
Any info would be appreciated.

THank you.  
Kind Regards  
Luis

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [6 June 2025 12:57 UTC](https://discourse.nodered.org/t/invalid-endpoint-message-when-using-node-red-contribut-opcua/97449/2 "2025-06-06T12:57:55Z")

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Best place to start would be read existing issues and raise a new one if needed:

> **[mikakaraila/node-red-contrib-opcua](https://github.com/mikakaraila/node-red-contrib-opcua/issues?q=is%3Aissue%20state%3Aclosed%20Certificate%20file%20must%20exist)**
>
> A Node-RED node to communicate OPC UA. Uses node-opcua library. - mikakaraila/node-red-contrib-opcua

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**Author:** ![Serhii\_Korol](https://avatars.discourse-cdn.com/v4/letter/s/58f4c7/32.png) [@Serhii\_Korol](https://discourse.nodered.org/u/Serhii_Korol)\
**Post date:** [29 July 2025 20:21 UTC](https://discourse.nodered.org/t/invalid-endpoint-message-when-using-node-red-contribut-opcua/97449/3 "2025-07-29T20:21:46Z")

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Hi Luis,

That error usually happens because the node-opcua library expects a certificate file to exist, even if you select _None_ for security. Twincat and UAExpert handle this internally, but node-red-contrib-opcua still tries to reference the default PKI folder.

You can fix it by:

- Manually creating the missing PKI folder and letting the node generate a self-signed cert on first run, or

- Switching the **security policy to "None" and security mode to "None"** in the OPC UA client config, then deleting any existing PKI folder so it regenerates cleanly.

Path for the certs:

```auto
vbnet

```

CopyEdit

`C:\Users\<YourUser>\AppData\Roaming\node-opcua-default-nodejs\Config\PKI `

Once the certificate files are there, the error should disappear.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [27 September 2025 20:22 UTC](https://discourse.nodered.org/t/invalid-endpoint-message-when-using-node-red-contribut-opcua/97449/4 "2025-09-27T20:22:46Z")

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