Exception: CoCreateInstanceEx: Class not registered

I am getting CoCreateInstanceEx: Class not registered Exception. Here's how I am trying to initialize the opc server:

Please advise.

```
var opcServerName = "FactoryTalk Gateway";
var opcServerIP = "192.168.200.7";

Uri url = UrlBuilder.Build(opcServerName, opcServerIP);

using (var server = new OpcDaServer(url))
{
  // read opc tags
}
```