Why apps are not downloading on Wifi?

[Windows Central Question]

Yesterday I flashed my Lumia 820. After flashing I tried to update apps via my home wifi, but update failed. But on mobile network it runs fine. Also I can surf, sync on mobile except apps are not downloading... Also I'm not able to download it on PC. What can I do..? I hard reset my mobile, reset my router.. But still facing same problem...