The library identifies itself to the mail server with a from address of "testing@example.com". It's probably a good idea to use an email address you own as the

The library identifies itself to the mail server with a from address of "testing@example.com". It's probably a good idea to use an email address you own as the from address if you want to use this in production, eg: "testing@mycorp.com", to avoid this grey-listing.