This article describes a scenario where you need to know your Clientnet main Account ID especially in certain situations where you need to integrate with different products such as Data Loss Prevention (DLP)
Email Security.cloud
There are different methods to find your Clientnet main Account ID :
A- In Administration > User Management page as shown below :
B- Lookup for the account name under Tools > Subscription Management
This should give you the details of your account under Account Reference tab.
C - Alternatively, Contact Support or Log a Support Ticket in order to provide you further details about your account reference.