I have three cases set up in the config. The first two will give the "vip" Oxide role on the server when someone is added to the donator or monthly donator roles in Discord. Those work fine. Now I added Discord Auth to the server and people send a code to a bot and they get the "authenticated" Oxide role on the Rust server. However, they are not getting the "Authenticated" Discord role after they've been given the "authenticated" Oxide role. Here's my config. I have verified that the Discord Role ID is correct:

{
  "Sync Nicknames": false,
  "Add Clan Tag To Nicknames": false,
  "Update Rate (Seconds)": 2.0,
  "Use AntiSpamNames On Discord Nickname": false,
  "Sync Data": [
    {
      "Oxide Group": "VIP",
      "Discord Role (Name or Id)": "834259513367592960",
      "Sync Source (Server or Discord)": "Discord",
      "Sync Notification Settings": {
        "Send message to Server": false,
        "Send Message To Discord": true,
        "Discord Message Channel (Name or ID)": "870628866052476978",
        "Send Message When Added": true,
        "Send Message When Removed": true,
        "Server Message Added Override Message": "",
        "Server Message Removed Override Message": "",
        "Discord Message Added Override Message": "",
        "Discord Message Removed Override Message": ""
      }
    },
    {
      "Oxide Group": "VIP",
      "Discord Role (Name or Id)": "836020767996117012",
      "Sync Source (Server or Discord)": "Discord",
      "Sync Notification Settings": {
        "Send message to Server": false,
        "Send Message To Discord": true,
        "Discord Message Channel (Name or ID)": "870628866052476978",
        "Send Message When Added": true,
        "Send Message When Removed": true,
        "Server Message Added Override Message": "",
        "Server Message Removed Override Message": "",
        "Discord Message Added Override Message": "",
        "Discord Message Removed Override Message": ""
      }
    },
    {
      "Oxide Group": "authenticated",
      "Discord Role (Name or Id)": "842828022587064372",
      "Sync Source (Server or Discord)": "Server",
      "Sync Notification Settings": {
        "Send message to Server": false,
        "Send Message To Discord": true,
        "Discord Message Channel (Name or ID)": "870628866052476978",
        "Send Message When Added": true,
        "Send Message When Removed": true,
        "Server Message Added Override Message": "",
        "Server Message Removed Override Message": "",
        "Discord Message Added Override Message": "",
        "Discord Message Removed Override Message": ""
      }
    }
  ],
  "Debug Level (None, Error, Warning, Info)": "None"
}

Can you set the debug level at the bottom of the config to "Info" and reload the plugin. It should display any errors with config. If the config is okay it will display why it's not adding the role or group.

It turns out I didn't have the DiscordAuth setting set to true in Discord Core Roles. All of the authenticated users were added to the Discord Authenticated group when I released. 

That makes sense. Glad it's resolved.