Hi ​@Abhilash BT,

Microsoft Remote Desktop supports two concurrent connections to remotely administer a computer. For more than two concurrent connections a Remote Desktop Session (RDS) or Terminal server license is required. Please refer to Microsoft for more information about RDS and Terminal Server Licensing. 

Here is a KB article on how to allow concurrent sessions:

Allow multiple RDP sessions for the same account - Allow concurrent check out for the same account.KB0016956.

Hope this helps,

Gloria