Hi @Shabin Suresh ,
which version of Windows 11 are you running?
Windows 11 Pro allows only one RDP session at the same time.
There is a Windows 11 version available supporting RDP multi-session. But as far as I know this is limited to use in Azure Virtual Desktop scenarios (https://learn.microsoft.com/en-us/azure/virtual-desktop/windows-10-multisession-faq#can-i-run-windows-10-or-windows-11-enterprise-multi-session-outside-of-the-azure-virtual-desktop-service).
If you search the internet you will find some "tweaks" around the termsrv.dll to enable RDP multi-session in Windows 11. But I doubt this is a supported option at Microsoft.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten