I created a transporter class to send emails:

export class MailTransporter {
  receiver: string;
  private transporter: Transporter;

  constructor(receiver: string) {
    this.receiver = receiver;
    this.transporter = this.getTransporter();
  }

  private getTransporter() {
    const { MAIL_USERNAME: user, MAIL_PASSWORD: pass, MAIL_HOST: host, MAIL_PORT: port } = process.env;

    if (!user || !pass || !host || port) {
      // NEXT LINE THROWS AN ERROR
      throw new Error('Specify MAIL_USERNAME, MAIL_PASSWORD, MAIL_HOST and MAIL_PORT in .env');
    }

    const transporter = nodemailer.createTransport({
      host,
      port: Number(port),
      secure: true,
      auth: {
        user,
        pass,
      },
    });

    return transporter;
  }

  public async sendMail(formValues: string) {
    const values: FormValues = JSON.parse(formValues);
    const message: SendMailOptions = {...};

    await this.transporter.sendMail(message, (err, info) => {
      if (err) {
        throw err;
      }

      console.log('Email successfully sent. Info:\n', info);
    });
  }
}

And calling sendMail function from within handler function:

export default async function Handler(req: NextApiRequest, res: NextApiResponse) {
  const { body } = req;

  try {
    const response = await MessageTransporter.sendMail(body); //MessageTransporter is an instance of MailTransporter

    res.status(200).json({ success: true, message: 'OK' });
  } catch (error) {
    res.json({ success: false, message: 'Could not send the message' });
  }
}

But the error thrown in MailTransporter isn't being catched in Handler, instead I'm getting the error in my console
And in my browser I'm getting 500 error on my POST request.

Could you please explain what's going on there? Why the error isn't catched inside try catch of handler?

Also, I'm kinda new to js classes so if you have anything to say about class design, please do.