MailGate has been upgraded to 5.0. Mail flow is re-enabled and emails are going through the device(s) but Message Tracking does not display information about any messages. The same happens with Email Traffic and Mail Stats charts.

Still, messages received before the upgrade are properly shown. Connections Tracking displays information for all current in- and outbound connections.

This is a frequent issue after the major upgrade to version 5.0.

The solution is to navigate to Admin UI >  Administration > Licenses > License Renewal and click the Download License button.

Once the license is downloaded, messages and their corresponding event details are displayed under the Message Tracking and Monitor graphs again.