First, preparation before activation:
1. If your iPhone uses a SIM card, please make sure that a SIM card is installed in the iPhone and that the iPhone needs a SIM card to activate.
2. When the SIM card is damaged, locked or lost, a warning of "No SIM card" or "SIM card is invalid" will appear.
3. If the information indicates to use Apple ID to log in for activation, please enter the Apple ID that you logged in on the iPhone for the last time to unlock activation.
Second, the operation steps:
1, please visit /support/systemstatus/ to view the list on the system status page. If the box next to "iOS device activation" is not green, please try to activate your iPhone later.
2. If prompted for a password, please enter it. The password prompt means that the activation lock may be enabled in Find My iPhone.
3. restart the iPhone.
4. If you use cellular mobile data connection, please try to connect to a reliable Wi-Fi network. If the Wi-Fi connection doesn't work properly, try connecting to iTunes.
5. If you use iTunes to activate your iPhone, please make sure that iTunes has been updated to the latest version.
Note: If the above steps cannot solve the activation problem, it is recommended that you contact Apple's official support 400-666-8800 (charge) for consultation.