@Rohit Kumar Jha Thank you for reaching out to us, could you help which account are you using to activate P2 license in your default tenant personal account or work/school account ?
Also did you get a chance to refer these QnA posts where similar issue has been discussed - https://learn.microsoft.com/en-us/answers/questions/1464265/i-cant-activate-the-trial-of-microsoft-entra-id-p2
If the above posts doesnt help, help me with more details like screenshot at time of issue so that I can better understand the issue and assist you. or you can reach me offline via email to 'AzCommunity@microsoft.com' with Sub - Attn: Givary and following details in the email body: Link to this thread/post We can connect offline and discuss further on this.