This issue may occur when Deep Security Manager is unable to communicate to the database. To verify if this is the cause of the issue, follow these steps:

1. In the Deep Security Manager directory, look for the server0.log file. By default, the directory is C:\Program Files\Trend Micro\Deep Security Manager.
2. Open the file and see the line similar to the following:

   SEVERE: Unable to start database sql exception

   If the line is present, it means that Deep Security Manager is unable to talk to the database.
    

   The line above is just a sample and the exact detailed reason may differ.

To prevent or resolve this issue, make sure that your database is up and running and that the machine where the Deep Security Manager is installed can communicate with the database.