You may be one of the users who can not download new Apps because you're having trouble using the App Store. If so try with the solution that we offer below. Sometimes, if the time or date of your iPhone, iPod touch or iPad is not properly configured, the App Store does not allow download new applications. It is a problem that does not always happen but it can be the case in some devices.
The way to fix it is very simple. All you have to do is go to Settings> General> Date and time> Automatic adjustment.
After a few minutes, the time of your iPhone should automatically adjust to the current. If you do not, you can change it manually. After getting a correct time and date, possibly the App Store will run smoothly again.
If the problem persists, it could be as simple fix. Many times when we changed version of iOS, Apple introduces changes to its policy that if we do not accept, prevent us from using the service. To correct this error, we go to Settings> iTunes Store and App Store and enter the data from our Apple account again. After the authentication, surely we asked to accept the terms and conditions of the App Store again (here's the problem that prevents us from using the store) and problem solved.
It could be Apple, and not our iPhone
After testing the options previously mentioned, if we continue to present problems for the connection, the problem may be Apple, and not us. We can see doing a simple Google search on if there are any problems with iTunes and iCloud servers.