# OPC UA connect to X20 fails due to certificate signet with SHA1

**URL:** <https://community.br-automation.com/t/opc-ua-connect-to-x20-fails-due-to-certificate-signet-with-sha1/10151>\
**Category:** HMI & Visualization\
**Tags:** x20, automation-runtime, opc-ua\
**Created:** [February 12, 2026, 9:06am UTC](https://community.br-automation.com/t/opc-ua-connect-to-x20-fails-due-to-certificate-signet-with-sha1/10151 "2026-02-12T09:06:25Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Nilson](https://avatars.discourse-cdn.com/v4/letter/n/FF8800/32.png) [@Nilson](https://community.br-automation.com/u/Nilson)\
**Post date:** [February 12, 2026, 9:06am UTC](https://community.br-automation.com/t/opc-ua-connect-to-x20-fails-due-to-certificate-signet-with-sha1/10151/1 "2026-02-12T09:06:25Z")

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Hello,

I am using

Automation Studio: 6.5.0.306

Automation Runtime: 6.5.1

OPC UA C/S: 6.5.0

I am trying to connect a controller to ABB 800xA via OPC UA.

I have an APC4100, for that the connection is working.

I also have an X20 (X20CP3687X). Here 800xA refusing the connection because it does not trust certificates that are singend with SHA1.

![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/3/3327080c26793f9b2e1a53e21bb8140da094d337.png)

How can I change how the X20 is signing the certificate?

Thanks

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<div class="post-metadata">

**Author:** ![tommi.piiparinen](https://dub1.discourse-cdn.com/brcommunity/user_avatar/community.br-automation.com/tommi.piiparinen/32/2183_2.png) [@tommi.piiparinen](https://community.br-automation.com/u/tommi.piiparinen)\
**Post date:** [February 12, 2026, 9:12am UTC](https://community.br-automation.com/t/opc-ua-connect-to-x20-fails-due-to-certificate-signet-with-sha1/10151/2 "2026-02-12T09:12:05Z")

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You should be able to follow the instructions in this post to create or use a SSL certificate for the OPC UA server.

[UAExpert, mappView: How to make a secure OPCUA connection to OPCUA server with communication partner validation](https://community.br-automation.com/t/uaexpert-mappview-how-to-make-a-secure-opcua-connection-to-opcua-server-with-communication-partner-validation/2414)

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<div class="post-metadata">

**Author:** ![Nilson](https://avatars.discourse-cdn.com/v4/letter/n/FF8800/32.png) [@Nilson](https://community.br-automation.com/u/Nilson)\
**Post date:** [February 12, 2026, 9:41am UTC](https://community.br-automation.com/t/opc-ua-connect-to-x20-fails-due-to-certificate-signet-with-sha1/10151/3 "2026-02-12T09:41:19Z")

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Thanks, that was the solution