Here the Top few reason which i experienced for Certification Failure
1.Make sure your App works in Full and Snapped View
2.Always make sure to uncheck the Internet Capability if you are not using any network connectivity in your Apps
3.Don’t forget to add Privacy Statement if you using network enabled Apps.
– Privacy Web Site Url
– Link Privacy Menu in Setting Charm menu to the appropriate location
4.The Website Link you are providing while submitting the apps should be up and running with proper content
The Microsoft Certification Crew are doing a great job in explaining what the exact reason for the failure. But still you can avoid these issues and can get through to store in few days rather than waiting for a week.
And Finally, What i noticed is, out of 3 Apps which i submitted, one of the App got failed.
It took 4 days to get notified for the certification failed. For rest of the App, i got the confirmation in just 2 days.