Check APN Settings
If you are not able to send even a single message SMS or MMS, then it could be a network issue. Check your APN settings. Search for your APN settings in our forums or on your favorite search engine.
Other things to check:
- SMS spam/block - make sure your friend/family is not blocked.
If you are using the default Messages app, then tap the 3 bars on top-left > “Spam & blocked”