the iPhone ------ cannot be updated at this time because the iphone software update server could not be contacted or is temporarily unavailable.

can anyone please give me some advice?

this solved my issue.

The hosts file may also be blocking the iTunes Store.

1. Open the Terminal utility located in Applications > Utilities.
2. When Terminal opens, open the hosts file by typing entering the following command and pressing Enter:
   sudo nano /private/etc/hosts
3. Type your user password when prompted.
   Note: This requires a non-blank admin password.
4. Edit the hosts file:
   The hosts file contains some comments (lines starting with the # symbol), as well as some default hostname mappings (e.g. 127.0.0.1 – localhost).
   You can navigate the file using the arrow keys.
5. If an entry is found containing apple.com, add # and a space to the beginning of that line.
   Note: If this is a work system, the hosts file may be used to redirect to local resources, such as software updates. Consult your support resources.
   
6. Save the hosts file.
   • When done editing the hosts file, press Control-o to save the file.
   • Press Enter on the filename prompt, and Control-x to exit the editor.