IPhone SMS photo shows that it hasn't been delivered yet. What happened?

Iphone Unicom number information can't be sent out, and there is a red exclamation mark behind the information. Self-test solution:

1. Call 100 10 to report the failure of mobile phone service. Please ask the service staff to tell us the number of the SMS center.

2. Enter ##5005*7672# (incoming call) to cancel the original wrong SMS center number.

3. Input: * 5005 * 7672 *+86 (130xxxxxxxxx correct SMS center number) # (long press 0 key to output+)

4. Input: *#5005*7672# Check whether the digital input is correct.

5. Mobile phone settings page-General-Network, turn off cellular data and 3G.

6. Mobile phone settings page-Information -iMessage, open.

7. restart.

8. Turn on cellular data and 3G.

Maybe some steps are redundant, but for safety reasons.