Hey @lisa2003, what model of phone you have? Restart your phone, leaving the device off for 3-5 minutes before turning it back on. Then take the SIM out of your phone, wipe it and put it back in. Make sure that your phone is up to date with the latest software and Apps: Settings > Software update > Download and install; then go to Galaxy Apps > Tap the three dots in the top right > My apps > Update. Now, head to: Settings > Apps > 3 dots (top right) > Show System Apps > Messages app and Phone app > Storage > Clear Cache. Also, make sure that you have enough credit to send the text. If you keep having issues, I recommend getting in touch with your Network Provider for further assistance.