Hi Kiran,
Try to performt the same by downloading the QC Explorer from the home page of the QC.
Provide the link of the QC, in that explorer & try a shot.
If still seems to be the issue, please check the version compatibility of your local machine with your QC Version.
Alternate, you can clear the temp folder and Internet cache for any application/Browser issues..seems to be.
Let me know, if you have the problem persisting..!
Thanks
Damodar Reddy