Hi Snehal,
In my case problem was with relationship which is maintained in the backend and when it was corrected the problem was sorted out.
However please understand that there can be multiple problems and is dependent on the user the way they are apporaching and doing it. Example: Issue with template like data not put in correct format etc..
So if you are doing the activity and if you are facing problem then please let me know, i'll look into it and will help as much as i can.
Cheers !!
Manish Jha