Unable to Connect to OPC UA Server - Error: BadCertificateUriInvalid (0x80170000u)

[tomytjandra]

Description:

I'm encountering an issue while attempting to connect to an OPC UA server using the client library. The connection fails with the following error:

public const uint BadCertificateUriInvalid = 0x80170000u;
// The certificate may not be used for the requested operation.

Code Snippet:

package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"github.com/awcullen/opcua/client"
	"github.com/awcullen/opcua/ua"
)

var (
	OPCUA_URL        = getEnv("OPCUA_URL", "")
	OPCUA_USER       = getEnv("OPCUA_USER", "")
	OPCUA_PASSWORD   = getEnv("OPCUA_USER", "")
)

// Environment variable helper
func getEnv(key, defaultValue string) string {
	if value, exists := os.LookupEnv(key); exists {
		return value
	}
	return defaultValue
}

func main() {
	fmt.Printf("Attempting to connect to OPC UA server at %s...\n", OPCUA_URL)

	ctx := context.Background()
	c, err := client.Dial(ctx, OPCUA_URL,
		client.WithSecurityPolicyURI("", ua.MessageSecurityModeNone),
		client.WithUserNameIdentity(OPCUA_USER, OPCUA_PASSWORD),
		client.WithInsecureSkipVerify(),
	)
	if err != nil {
		log.Fatalf("❌ Failed to connect: %v", err)
	}
	fmt.Println("✅ Successfully connected to OPC UA server!")

	defer func() {
		c.Close(ctx)
		fmt.Println("🔌 Disconnected from OPC UA server.")
	}()
}

Attempts:
I have tried the following but still encountered the same error:

1. Ignore server certificate verification using WithInsecureSkipVerify() → Failed
2. Attempted anonymous connection (without authentication) → Failed
3. Generated a self-signed certificate (cert.pem and key.pem) → Failed

Is there any specific configuration required on the client or server side to bypass this certificate validation issue? Any guidance would be appreciated.