Newly created users are required to authenticate their email the first time they log in to Barracuda RMM as part of the user creation process. See Creating a User Account for more information.
Users are also required to authenticate their email if they change the email address in their user profile.
Email validation links are sent to users automatically during the process of creating new users and changing user email addresses. However, if the user has not clicked the validation link, you can send another validation email. You may need to do this if a user doesn’t validate their email within a day of the email being sent, because but validation links expire in 24 hours.
On the User Management page, users whose email validation is pending have the following icon next to their email address: 
Email Validation for Users who Access Multiple VARs
Users who access multiple VARs may be required to validate their email address for each VAR they access. A request is sent when a user who has not validated their email address modifies their user profile. When the modification is saved, that a user whose email address is not validated is logged out and must validate their email address in order to log in. The validation link is sent to their email address. Users are only required to validate their email once per VAR.
If you do not access multiple VARs, this does not apply to you.
To send a validation email to a user
- In Service Center, click Configuration > Users & Roles > User Management.
- Click the name of a user whose email is pending validation.
- On the Profile tab, click Send Email Validation.
- Click OK.