Mail sending not working

Hi everyone, I’m new, this is my first question here.

I am trying to use nodemailer.
Upon user action, a letter should be sent to the address I specified.
I set everything up and checked it on localhost, but on netlify
Letters do not reach, nothing happens. After some custom time (more than a day, up to 3 days), a letter arrives at the mail that the sender says that the address does not exist, or exists, but the quota has been exceeded. The problem is that some Google addresses are specified as the recipient, also custom, but the first letter is “j” of the type (johnvinodkumar@gmail.com, jojit@gmail.com or another). that is, somewhere in the process the address indicated by me is substituted.

the address of both the sender and the recipient indicated by me is in no way connected with Google.

In addition, I tested my application on heroku, and everything works fine there.

What could be the problem?

Try this:

and several other posts on these forums