Here is how to fix it:
Make sure you’re using the most current version of iTunes. To check, take these steps:
1. Open iTunes.
2. From the iTunes menu, choose About iTunes.
3. If your version isn’t 11 or above, download the latest version for free here: http://www.apple.com/itunes/download
If you use Safari, make sure you’re running the latest version. To check, follow these steps:
1. Open Safari.
2. From the Safari menu, choose About Safari. The version number will display:
• If your Mac is running OX X v10.9, your Safari version should be 7.0.
• If your Mac is running OS X v10.7 or OS X v10.8, your Safari version should be 6.1.
• If your Mac is running OS X v10.6.8, Safari should be 5.1.10.
• If your Mac is running OS X v10.5.8, Safari should be 5.0.6.
To update Safari, go to the Apple menu and choose Software Update.
If you have a firewall, your settings may be blocking iTunes from connecting to your computer. It’s simple to check your firewall settings:
1. From the Apple menu, choose System Preferences.
2. Click Security & Privacy.
3. Click the Firewall tab.
4. Click the lock and enter your admin password.
5. Select Automatically allow signed software to receive incoming connections.
6. Restart your computer and check if you can connect to iTunes.
To add music, please check out the article below:
https://support.apple.com/en-us/HT204839
Thanks to Jerson from iTunes Support!
