Certificate error in Node-RED


After using the OPC UA Client node in Node-RED, sometimes you might see “invalid endpoint Error” as shown below:


  • You must generate new private_key.pem using Git Bash terminal
  • Install and open Git bash terminal. Type this code: openssl req -newkey rsa:2048 -nodes -keyout private_key.pem -x509 -out client_selfsigned_cert_2048.pem
  • Two files will be created in your root folder: client_selfsigned_cert_2048.pem and private_key.pem
  • In your documents, create a new folder called Self_certificate and move the two pem files into this folder
  • Also place a copy of private_key.pem into following directory: C:\Users<Username>\AppData\Roaming\node-red-opcua-nodejs\Config\PKI\own\private
  • In the edit window of OPC UA client, you must use Local certificate option and provide path for client_selfsigned_cert_2048.pem and private_key.pem files
  • They were both placed in the folder ‘Self_certificate’ created in Documents folder
    • C:\Users<Username>\OneDrive\Documents\Self_certificate\client_selfsigned_cert_2048.pem
    • C:\Users<Username>\OneDrive\Documents\Self_certificate\private_key.pem
Also, it is a good idea to start a new node-red project with Encryption disabled before using the OPC UA Client node