Why can't I send text messages when upgrading ios 10?

The SMS function added by iOS 10 cannot be used. Solution:

What should I do if I doodle in imessage and find that the message can't be sent out? First, you turned off the imessage function before, and second, you didn't turn on the 3d touch function.

How to set ios 10 imessage:

1. After connecting the iPhone to the network, find the "Settings" icon on the iPhone's home screen, and then click "Open".

2. Find the Info option in the settings list, and then click Enter.

3. Click the iMessage switch to turn it on.

4. Waiting for activation of iMessage service will be displayed.

5. After successful activation, you can see that the switch of iMesaage is on. The other two options that need to be clear are:

First, send a read receipt to let the other party see the time when we read the information.

Second, when iMessage is unavailable, it will be sent by SMS, which means that when there is no network or Apple's iMessage information service fails, the system will automatically send it by SMS.

6. Select the friend who wants to send iMessage, and do the same operation as sending normal SMS. The iMessage message will be displayed in blue, and the word iMessage will appear in the SMS input box.