1) CHECK YOUR CONNECTION- Make sure that your device is connected to the Internet.
- Disconnect to the University WIFI network.
- Try to connect your laptop outside university WIFI network.
- or connect your laptop to your mobile data
- Check you Appstore
2) Update your software
- Update your O.S version of your device ( iOS, macOS, and iTunes)
3) Update your Account
- update your apple id
- If you recently changed your Apple ID or password, you might have to sign out and sign back in.
4) Check the Time and Date