The mail rescue mode for the mail backup should be kept at OFF mode. Once mail rescue is turn on, emails routed to our email server will end up at our mail rescue server directly instead of being forwarded to your mail server.
You only need to turn on mail rescue when your mail server is down and going to be down for very long time. In case when your users can't wait until you fixed your server, you may turn on the mail rescue so that your users can use our webmail or POP/IMAP to read/reply their emails.
Bear in mind that you don't need to create the email box address in advance. You can wait until your mail server is down and our system got your emails, the email addresses will be automatically pick up and presented as check boxes to select, saving you time to enter all the email addresses. You can assign the same password to all the emails (can be changed later).
The webmail URL to get mail rescue emails is webmail2.dnsexit.com. You should use the email address in lower case and the password assigned to the address to login to check emails.
To access the mail rescue emails directly through POP/IMAP, you can point the POP/IMAP/SMTP server name to mailrescue.dnsexit.com at your user's email client. The login is the email address(lower case) and the password is the one assigned to the email (when you create the mail rescue email box).