There's an ever-growing list of stuff you need to set up to be considered a legitimate mail server. It started long ago with a valid reverse DNS entry, and now

There's an ever-growing list of stuff you need to set up to be considered a legitimate mail server. It started long ago with a valid reverse DNS entry, and now you need DKIM, SPF and a bunch of other stuff: https://support.google.com/mail/answer/81126?hl=en https://support.google.com/mail/answer/81126?hl=en Given that banks seem unable to send e-mail that doesn't look like phishing (using non-https links and often separate domains), I don't have high confidence that they can get the basics right.