Greetings denox,
I'm curious whether you're accessing a Windows client machine or a server remotely. It's worth noting that the Windows client operating system doesn't accommodate multiple simultaneous remote connections.
When you work with a server OS, only 2 administrative sessions can be active concurrently. To enable additional connections, you'll need to set up Remote Desktop Services and acquire the necessary RDS Client Access Licenses (CALs).
Provided you've got the RDS role and the correct licensing, you can ensure your CALs are properly configured by following these steps outlined in this guide: Troubleshooting Cannot connect to RDS because no RD Licensing servers are available - Windows Server | Microsoft Learn
For a more detailed error message, you should check the event logs. Here’s how to do it for server environments: Remote Desktop Services Events (by Role Service) in Windows Server 2008 R2 | Microsoft Learn
On client machines, look into these log files for insights:
- Microsoft-Windows-RemoteDesktopServices
- Microsoft-Windows-TerminalServices
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