When you create users in AuthPoint for your network, AuthPoint automatically sends an activation email to the address for each user account.
If the destination email service sends back a failure message for the user, AuthPoint suppresses that user email address. If this occurs, WatchGuard Support must remove the suppression before the user can receive activation emails from AuthPoint.

To confirm this issue, you can check in a few places:

1.      If you use WatchGuard Log Server, Dimension, or WatchGuard Cloud to collect log messages for your Firebox, search for emails sent by wgcloud-no-reply@cloud.watchguard.com to the user email address in question.
The log messages might help you identify if the email was delivered, or failed because of Firebox policies.

2.   In the log messages for your internal email server, search for email rejection messages with codes like 550 Unknown Recipient/User. 5XX response codes indicate a permanent rejection.
For example:
550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient myuser@domain.com not found by SMTP address lookup
550 5.1.1 <myuser@domain.com>: Recipient address rejected: User unknown

For assistance, contact WatchGuard Support Online.  When you do, make sure to include any impacted email addresses in your support case.