Hi Aravind,
In the portal, please verify that the new VM was created with Standard security. You can check this on the Overview tab, scroll down and look for Security type: Standard. Reason I want you to check is sometimes when creating via the portal it will switch security back to trusted launch when you change one of the other options.
Please click Accept Answer if the above was useful. If the above doesn't solve the issue please leave a comment with specific details/screenshot of the error you are seeing.
Thanks.
-TP