Calling the graphClient is giving an exception: AADSTS9002313: Invalid request in c#

Hi, I am trying to access the signed-in user name, using the Graph client created in c#. But getting the following error. 

InnerException = {"AuthorizationCodeCredential authentication failed: AADSTS9002313: Invalid request. Request is malformed or invalid.

The exception was thrown at this line

var user = await graphClient.Me
.Request()
.GetAsync();

I do not know what is wrong here. Need help.

Thanks in Advance.