Google constantly does server-side testing for their new features and UI changes on few chosen users at a time. But some times these test go haywire and create difficult situation for the users. Recently, Google has broken the Play Store and Google Now for some users, as a result of two independent server-side tests.
This time around the server-side tests have broken two of Google’s most significant Android apps. The Google Play Store issue is causing the homepage to show blank. But you can still search, install and update apps. As there is no workaround for this issue. You will have to wait for a fix from Google.
Similar test have also affected Google Now as the cards are malfunctioning, causing an error message to appear in the main screen. However, there is a solution for this issue. Go to Settings > More > Application Manager > Google App > Manage Storage > Clear Google Search Data. Open up Google Now again, and your cards should be there.