TypeError: Cannot read property 'parameter' of undefined

Question

Disclaimer: I am not knowledgeable about Google Script, so detailed explanations of the issue would be much appreciated

My goal is to reproduce the steps from this page: https://www.labnol.org/send-sms-google-sheets-200402

However I receive the following message while trying to Debug doPost.

The full script used is:

const SHEET_URL ="myurl";

const SHEET_NAME = "SMS";

const doGet = () => {
    const sheet = SpreadsheetApp.openByUrl(SHEET_URL).getSheetByName(
        SHEET_NAME
    );
    const [header, ...data] = sheet.getDataRange().getDisplayValues();

const PHONE = header.indexOf('Phone');
const TEXT = header.indexOf('Text');
const STATUS = header.indexOf('Status');

const output = [];

data.forEach((row, index) => {
        if (row[STATUS] === '') {
            output.push([index + 1, row[PHONE], row[TEXT]]);
        }
    });

const json = JSON.stringify(output);

return ContentService.createTextOutput(json).setMimeType(
        ContentService.MimeType.TEXT
    );
};

const doPost = (e) => {
    const sheet = SpreadsheetApp.openByUrl(SHEET_URL).getSheetByName(
        SHEET_NAME
    );
    const [header] = sheet.getRange('A1:1').getValues();
    const STATUS = header.indexOf('Status');
    var rowId = Number(e.parameter.row);
    sheet.getRange(rowId + 1, STATUS + 1).setValue('SMS Sent');
    return ContentService.createTextOutput('').setMimeType(
        ContentService.MimeType.TEXT
    );
};