The error: Users can't connect via RDP. The exact message is usually "The remote session was disconnected because there are no Remote Desktop License Servers available to provide a license." It often appears suddenly, on a server that's been accepting RDP connections fine for months.
Environment: Windows Server 2016 through 2025, any edition running the Remote Desktop Session Host role.
Why this happens: Windows Server ships with a 120-day RDS licensing grace period that starts the moment the Remote Desktop Session Host role is installed — not when you configure licensing. If a proper RDS license server with valid CALs (per-user or per-device) isn't configured before that grace period expires, RDP access simply stops. This catches people specifically because the server usually was set up correctly for RDP access itself; what's missing is the separate, easy-to-forget step of pointing it at a license server before the clock runs out.
The fix:
- Confirm you actually have RDS CALs purchased and a license server available — this is a licensing prerequisite, not just a config toggle.
- Open Server Manager → Remote Desktop Services → Overview → Deployment Overview, and set the RD Licensing role and licensing mode (Per User or Per Device) to point at your license server.
- If no license server exists yet, install the RD Licensing role (can be the same server for small deployments) and activate it via the Licensing Manager console.
- Restart the Remote Desktop Session Host service, or reboot, for the change to take effect.
One thing worth knowing: if you're in a genuine emergency and just need access back today while you sort out real licensing, a registry-based grace period reset exists — but treat it as exactly that, an emergency measure, not a fix. If it's happening on a production server, get real licensing sorted rather than resetting the clock repeatedly.