What does Apple's SMS question mark mean?

There is an exclamation mark in Apple's mobile phone text message, indicating that the message failed to be sent. In the setting information, right-click the iMessage option and restart.

Set the phone call forwarding function to see if it is turned on and off.

1, the mobile phone supports 4G.

2. The mobile phone card supports 4G.

3. There is 4G network signal coverage in the local area.

4. Is the 4G switch on?

Without the 4G solution: 1, the mobile phone may not update the mobile network settings, so the mobile phone should update it when prompted to update. 2. The mobile phone card is opened for 4G, and the 4G package is opened. 3. If there is no local 4G network or the 4G data signal is poor, there is no way out. 4. Turn on the 4G switch.