Article - CS324697
Error "Client or Server Certificate is invalid" when using OPC UA Client driver in PTC Kepware Products
Modified: 20-Aug-2025
Applies To
- Kepware Server (formerly KEPServerEX) 6.0.2107.0 to 6.18
- ThingWorx Kepware Server (legacy) 8.0 to 6.18
Description
-
Error in event log when using OPC UA Client driver:
The Client or Server Certificate is invalid. Please use the OPC UA Certificate Manager to configure the certificate
- The server certificate has been trusted successfully in the OPC UA Certificate Manager > Trusted Servers
- The certificate is self-issued and self-signed
- Secure OPC UA connection to Siemens S7-1500 fails with certificate error
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