For activate encrypted connection between Clients and Microsoft SQL Server, configuration must done from Configuration Manager. But, even SSL certificate imported on operating system, list of certificates can be empty. This will be happen, when a non-administrator service account assigned for SQL Server service on operating system.
For see certificates on SQL Server Configuration Manager, service account must have Full control on certificate.
After that configuration, certificate will be appear on SQL Server Configuration Manager.
Restart SQL Server for activate encrypted communication.