Capture HTML Form Responses in Google Sheets and send a Confirmation Email to the Form Submitter - forms

Question

I want the script to send the created html email template email.html to the person who last submitted the form.
Below is the success message I get in the console:
Below is the actual email that is received by the person who submits the form:
The email.html is formatted correctly and appears perfectly when sent manually.
I hope this is reprex enough.
EDIT: Maybe it's easier if I include the code
function sendEmail () {
var ss = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
var lr = ss.getLastRow();
var data = ss.getRange(lr,3);
var email = data.getValue();
var message = HtmlService.createTemplateFromFile('email');
var subject = "Test Subject"
GmailApp.sendEmail(email,subject, message);
}

Answer 1

It's not clear why you are using HtmlService.createTemplateFromFile, but from the image it's clear there at least one error, the script misses two methods:
HtmlService.HtmlTemplate.evaluate() to evaluate the Templated HTML
HtmlService.HtmlOutput.getContent() to get the HTML from the HtmlService.HtmlOutput object returned by the previous method.
Another option that looks to be an error is the use of GmailApp.sendEmail(string,string,string) method, as the third parameter should be a string to be used as the email plain text content. If you want to pass HTML, instead use GmailApp.sendEmail(string,string,string, Object)
Related
Emailing Google Sheet range (with or without formatting) as a HTML table in a Gmail message
Sending an email in HTML and plain with a Gmail Apps Script
Google script inject html into html email
References
https://developers.google.com/apps-script/guides/html
https://developers.google.com/apps-script/guides/html/templates
https://developers.google.com/apps-script/reference/gmail/gmail-app#sendEmail(String,String,String)