Troubleshooting Tip: Current Active users displayed in the Dashboard, doesn't match 'real' active users

The FortiMail Cloud service is licensed by the number of users.

Sometimes the FortiMail Cloud dashboard shows more active users than licensed ones:

An alarm icon is displayed close to the limit; this means the license was exceeded.

The daily calculation of active users is based on the last 30-day period. The FortiMail searches for all the protected domains' users who have received/sent messages in the last 30 days. If a user has not received a message in the last 30 days, it will be removed as an active user by tomorrow, as long as a new message is not received/sent from/to this user.
The list of users counted as active can be displayed in the view Domain -> Domain. Select the active users column for a specific protected domain, and it will display the list of active users:

This list can be downloaded in .csv format for further analysis, if required:

It is recommended to activate the 'Recipient Address Verification' option to avoid non-existent users being counted as active.

This can be done by performing the following steps:

1. Domain & User -> Domain -> Find Protected Domain -> Edit -> Recipient Address Verification.
2. Choose 'SMTP Server' or 'LDAP Server'.

If the server cannot perform the Recipient Address Verification, create an LDAP Profile by going to Profile -> LDAP  -> LDAP -> New -> Configure the Profile as needed -> Create.

More information is available in the following document (page 5):

FortiMail Cloud SMTP Recipient Verification with Microsoft 365