ethereal | A command-line tool for managing common tasks in Ethereum | Command Line Interface library

Turns out that Ethereal Email, the service Nodemailer uses for test emails, is down:

• https://ethereal.email/ doesn't load
• https://www.saashub.com/ethereal-email-status - says it's down

This is most likely the issue.

Instead of the dubious:

transporter.sendMail returns a promise, that's why your console log has undefined. So either attach a .then and .catch.

SLS 8.1.3 Pattern Binders states

A pattern p implies a type T if the pattern matches only values of the type T.

The pattern Earthy(i) in

http://ethereal.email/

Ethereal is a fake SMTP service, mostly aimed at Nodemailer users (but not limited to). It's a completely free anti-transactional email service where messages never get delivered.
Instead, you can generate a vanity email account right from Nodemailer, send an email using that account just as you would with any other SMTP provider and finally preview the sent message here as no emails are actually delivered.

Even if not, the server logs in console that the message has been sent with no errors the message you get is that the SMTP server successfully accepted your mail and added it to the send queue, but that will not guarantee that it will be delivered. The receiving SMTP server could still reject it and send a bounce message back.

At the transporter options, if you use gmail at the auth, you need to add
auth: { user: 'youremail@gmail.com', pass: 'yourpassword' }
You must also know that you are the only one that can send email to other users.
When sending email at the transporter the from: process.env.EMAIL_ID can only be your email, not anyone else's.
If you use yahoo it will be a bit more tricky to send emails, because you need to add an application password in order to authenticate.

It turns out nodemailer is not very reliable due to it is not recognized as a 'trusted application' unless your server itself is trusted by Google. And that seems to be reducing your reputation and cause the email to be rejected.

Best solution I can find for now is to use some paid mailing service like Mailchimp. Just don't use Nodemailer if you don't have to.

Sorry cannot write this as a comment as including the output is necessary. I was trying things with your code and when I changed the host and the wireshark-labs part ..a strange thing happened. I changed it to s.sendall(b"GET / HTTP/1.1\r\nHost: www.cnn.com\r\n\r\n") to understand how this works... and the response I get is...

If the value is obtained asynchronously, you cannot export the final value (with current versions of node.js). At the time of the exports, the value is not yet known so all you can really do is export the promise and anyone who wants the value will have to use await or .then() on the promise to get the value.

There are proposals to support asynchronous exports so the loader itself will block and wait for asynchronous values (to make problems like this easier), but that is not yet available for use.

Another thing I have occasionally done is to not launch the meat of the app until some asynchronous value has been obtained and placed into a variable where it can be retrieved synchronously. If your code is a server, that would usually involve not starting the server until the async value is available and stuffed into a variable. Thus, no request handler can occur before the async value is in that variable and it can then essentially be used synchronously.