Issue:
You get an email alert that looks like this:
Explanation:
You probably have SMTP Discovery turned on. Usually with most clients, if they are not using Office365 Azure Sync or AD Sync, like Google Workspace clients for instance, we use SMTP Discovery instead. What SMTP DIscovery does, in a nutshell, is something like this:
- Proofpoint receives an email for a user@yourdomain.com
- If Proofpoint sees the user doesn't exist, it accepts the email and puts user@yourdomain.com in the "Discovered" list
- Proofpoint sends the TECH CONTACT in your Proofpoint tenant to advise you "hey, I see we're starting to get emails for this user"
- The action you need to take is going to be either convert the user to an end user or mark it as invalid.
- If proofpoint keeps getting emails for that user without you taking any action, after three contact attempts (alerts sent to you), it will automatically mark the user as invalid and reject from that point on.
So what this means is you need to take action if the mailbox is actually legitimate.
Solution:
Login to proofpoint essentials
Go to User Management -> SMTP Discovery
From the pulldown, select "Discovered List"
Find the user that you are getting notifications about and then decide, from the pulldown, what you want to do with it.
That's it - you should no longer get alerts about the user.