As many users have pointed out, some of Apple’s online services including iTunes and the App Store are experiencing downtime. Different error messages are popping up when the various services are opened or upon trying to connect.
The outage appears to be global, as users in several countries have reported experiencing difficulties.
You can head to Apple’s System Status page to get a look at which services are currently affected by the outage.
We will be sure to keep an eye on the situation and report any updates.
UPDATE: According to Apple’s System Status page, the issue has been resolved as of about 3:10 p.m. central time. In a statement, Apple pointed to an internal DNS error as the cause of the outage.
Apple: “DNS error” responsible for ongoing iTunes, App Store outages
http://arstechnica.com/apple/2015/03/apple-dns-error-responsible-for-ongoing-itunes-app-store-outages/