Fail to send email: data is not defined

Question

I am just getting this error message: Failed to send email: data is not defined.

...What I am trying to do is to implement resend library into my project. I've made an email template, it is working as intended, form submission is working too, but when I come to this part... I am just getting this error.

/** @format */

import { NextResponse } from "next/server";
import { Resend } from "resend";
import EmailTemplateWelcome from "@/app/emails/EmailTemplateWelcome";

const resend = new Resend(process.env.RESEND_API_KEY);

export async function POST(request, response) {
  try {
    const body = await request.json();
    console.log("body", body);

    const {
      firstName,
      lastName,
    } = body;

    console.log("firstName: ", firstName);

    const data = await resend.emails.send({
      from: "[email protected]",
      to: "[email protected]",
      subject: "Getting The Error",
      react: EmailTemplateWelcome({
        firstName,
        lastName,
      }),
    });

    return NextResponse.json(data);
  } catch (error) {
    if (error instanceof Error) {
      console.log(`Failed to send email: ${error.message}`);
    }
    return NextResponse.json(
      {
        error: "Internal server error.",
      },
      {
        status: 500,
      }
    );
  }
}