I cannot update iTunes Program

Hi Guys,
An error message appears when I clicked on the “Check for Update” button in iTunes. I have a web connection. I am connected to the internet by way of an Ethernet Cable and I can access the iTunes store in iTunes.
For ages now I have been trying and it says try again later. Is the problem with Apple or iTunes? Please, look at the error message on the screenshot and give me a solution.
Error:
The iPhone software server could not be
contacted.
Make sure your network settings are correct and your network
connection is active, or try again later.
