Fetch XML Connection Giving Error

Hello All,

I am developing reports in MS CRM 2013 and everything was working fine. Reports was fetching the data using Fetch XML. But from yesterday it is not working giving Error:

LogonIdentityExWithUI()
----------------------------
An authentication error occurred while connecting to server "https://<url>/Services/2011/Discovery.svc". Make sure that the connection string and credentials are correct, and try again. 

Whereas I am able to logged in with the same userid and password to connect CRM that its working fine from browser.

Any help would be appreciated.

Thanks

Thanks Prashant Sharma