The Email Security solution has two levels of access - MSP and Customer, one of which your login account is based on. An MSP admin can drill down from the MSP level to the customer level to view and manage their customer accounts. See Levels of Access for Email Security.
There are a number of options to move between the MSP and Customer levels:
Breadcrumb: You can travel up and down levels using the breadcrumb at the top of the page.
Menus: Select or search for a customer from the dropdown menu on the left. Use the breadcrumb to navigate back to MSP level.
Overview page: An MSP Admin can select the view
icon for a customer in the All Customers table. Use the breadcrumb to navigate back to MSP level.