itunes not showing app updates

I have iTunes version 12.1.2.27 installed on a yosemite mac. For the past week, iTunes will not show app updates when I go to the apps and check for updates. I can see that there are updates available for some of my apps in my iPad and iPhone however these will not show up on iTunes. When I go to individual apps that have available updates on iTunes, I can see the update button below the app icon on App Store.

So far I have tried:

1) Reinstalling Itunes

2) Logging out and in to my iTunes account

3) Multiple reboots and cold boots

4) Resetting all dialog warnings and iTunes store cache from iTunes Adcanced Preferences.

When I hit check for updates, iTunes briefly displays Accessing iTunes Store but then no updates are found.

Please help

Mert