Title: Discord API returns 403 'internal network error' (Code 40333) when bot adds reaction via Google Apps Script

[Kenneth Roger Gavino]

I am developing a Discord bot using Google Apps Script. The bot's primary function is to post an approval message as a reply in a channel and then immediately add a '👍' reaction to its own message.

While the message posting works perfectly, the subsequent API call to add the reaction fails with a very specific error:

*   **HTTP Response Code:** `403`
*   **Response Body:** `{"message": "internal network error", "code": 40333}`

This is confusing because my bot has the **Administrator** role in the Discord server, which should grant it all necessary permissions.

#### **The Workflow**

1.  A user triggers an action in a Google Sheets-backed web app.
2.  The `processApproval` function is called in Google Apps Script.
3.  `sendBotReply` successfully posts a message to the correct channel via the Discord API. It returns the new message's link/ID.
4.  `addDiscordReaction` is called immediately with the new message's details. **This is the step that fails.**

#### **Relevant Code (Google Apps Script)**

Here is the simplified code for the core logic. The `sendBotReply` function is included to show that `UrlFetchApp` and the Bot Token are working correctly for posting messages.

```javascript
const BOT_TOKEN = '...'; // My bot token is valid and works for posting.

/**
 * Main orchestrator function.
 */
function processApproval() {
  try {
    // This part works: The bot posts the message and I get a valid link.
    const messageLinkFromBot = sendBotReply();

    // This is the call that fails.
    addDiscordReaction(messageLinkFromBot);

  } catch (error) {
    Logger.log('Error in processApproval: ' + error.toString());
  }
}


/**
 * Sends a message as the bot. THIS FUNCTION WORKS.
 * Returns the URL of the newly created message.
 */
function sendBotReply() {
    const channelId = '123456789012345678'; // Example Channel ID
    const apiUrl = `https://discord.com/api/v10/channels/${channelId}/messages`;

    const payload = {
        content: `This is a test message from the bot.`
    };

    const options = {
        method: 'post',
        contentType: 'application/json',
        headers: {
          'Authorization': 'Bot ' + BOT_TOKEN
        },
        payload: JSON.stringify(payload),
        muteHttpExceptions: true
    };

    const response = UrlFetchApp.fetch(apiUrl, options);
    const responseData = JSON.parse(response.getContentText());
   
    // Example return: "https://discord.com/channels/SERVER_ID/CHANNEL_ID/MESSAGE_ID"
    return `https://discord.com/channels/${responseData.guild_id}/${responseData.channel_id}/${responseData.id}`;
}


/**
 * Tries to add a reaction to a message. THIS FUNCTION FAILS.
 */
function addDiscordReaction(messageLink) {
  // Assume parseDiscordLink correctly extracts IDs from the messageLink
  const ids = parseDiscordLink(messageLink);
  // ids = { channelId: '...', messageId: '...' }

  if (!ids) {
      throw new Error(`Could not parse IDs from message link for reaction: ${messageLink}`);
  }
 
  const reactionEmoji = encodeURIComponent('👍'); // Thumbs Up
  const url = `https://discord.com/api/v10/channels/${ids.channelId}/messages/${ids.messageId}/reactions/${reactionEmoji}/@me`;
 
  const options = {
    method: 'put',
    headers: {
      'Authorization': 'Bot ' + BOT_TOKEN
    },
    muteHttpExceptions: true
  };

  const response = UrlFetchApp.fetch(url, options);
  const responseCode = response.getResponseCode();
  const responseBody = response.getContentText();

  // THE PROBLEM IS HERE:
  // responseCode is 403
  // responseBody is {"message": "internal network error", "code": 40333}
 
  if (responseCode !== 204) {
    Logger.log(`Failed to add reaction. Code: ${responseCode}, Body: ${responseBody}`);
    throw new Error(`Failed to add reaction. API responded with code ${responseCode}.`);
  }
  Logger.log(`Successfully added reaction to message ${ids.messageId}`);
}

// Helper function to extract IDs
function parseDiscordLink(link) {
    if (!link) return null;
    const match = link.match(/channels\/\d+\/(\d+)\/(\d+)/);
    if (match && match.length === 3) {
        return { channelId: match[1], messageId: match[2] };
    }
    return null;
}
```

#### **What I've Checked**

1.  **Permissions:** The bot has the **Administrator** role. This includes `Add Reactions` and `Read Message History`.
2.  **Bot Token:** The token is correct and has the necessary scopes (`bot`, `applications.commands`). It works perfectly for the `sendBotReply` function.
3.  **API Endpoint:** The URL `.../reactions/{emoji}/@me` with the `PUT` method is correct according to the [Discord API documentation](https://discord.com/developers/docs/resources/channel#create-reaction).
4.  **IDs and Emoji:** The `channelId`, `messageId`, and URL-encoded `emoji` are all correct. I have logged them and they are valid.
5.  **Timing:** I tried adding a `Utilities.sleep(2000)` between posting and reacting, but it made no difference.
6.  **Error Code:** The error is not the typical `50013: Missing Permissions` error. The `40333: internal network error` seems to indicate something else is wrong.

#### **The Question**

What could be causing this specific `40333: internal network error` when trying to add a reaction? Given that the bot has full Administrator permissions and can successfully post the message it's trying to react to, what could be the root cause? Is this a known issue with Google Apps Script's `UrlFetchApp` or a more obscure Discord API behavior?