The remote session was disconnected because there are no Remote Desktop License Servers available to provide a license

1. If you have RDS deployment, did you create a session collection and make your RDSH server part of the collection?

2. In Server Manager -- RDS -- Overview -- Deployment Overview -- Tasks -- Edit Deployment Properties -- RD Licensing tab, did you set the Licensing mode and add the FQDN of your RD Licensing server?

3. If this is a standalone RDSH server (i.e. you didn't create an RDS deployment via Add roles and features), did you configure the licensing mode and licensing server name using group policy?  For example, you could use gpedit.msc and configure the below settings:

Computer Configuration\ Administrative Templates\ Windows Components\ Remote Desktop Services\ Remote Desktop Session Host\ Licensing

Use the specified Remote Desktop license server     Enabled

Set the Remote Desktop licensing mode     Enabled