Solutions:
1. Turn on the data switch again.
2. Replace access point (NET/WAP) and try to reset APN if none is available.
3. Turn on/off flight mode.
4. Check for overdue payment.
5. Check whether other mobile phone using the same Internet can access the Internet.
6. Check that access is disabled in mobile date.
7. Check that access is disabled for third-party apps.
8. Back up data and restore factory settings.
9. Update to the latest system version.
10. If the above methods can not solve the issue, it is recommended to go to local after-sales center for inspection.
