The recipient will see this in their inbox
The recipient clicks on Read the message and a web page will open (could take up to 10 seconds to load the page)
Choose Sign in with One-time passcode, and you will receive a second email with the One-Time passcode
They will see this message.
They will receive a passcode at the same email address (have them check Spam folder if they don't see it). Have them copy and paste.
