Why can't my Apple phone send a text message to my husband's phone?

1, learn about iMessage: Apple's iMessage uses the network to send messages to each other, instead of taking short messages. When it judges that you are sending an Apple phone, it will automatically switch to sending iMessage messages, and the color block of the short message will be blue.

2. Solution: You and your husband both go into the settings of their mobile phones, find the information, and turn on and off iMessage inside.

The reason for this problem is one of the network problems.