As per your query, we would request you to kindly perform the following steps to resolve your issue.
If it is one number, try to send text message on another number.
If you're unable to send any SMS (text) messages to any contacts, it suggests that your network operator's message center number stored in your device's settings is either missing or wrong.
Follow these steps to check, and if necessary correct, that number.
Go to the Apps screen>>Tap on Messages>> Tap on More (three dots)>> Tap on Settings>>Tap on More settings>>Tap on Text messages>>Tap on Message Center
(Check your network operator's website for their message center number to compare). If the number on your phone is different, or missing, tap Message center, enter your network operator's message center number and then tap SET. Then try sending a text message.
Clear the Messaging app's data Please follow the below steps: Go to Settings>>Tap on Apps>>Tap on Messages>>Tap on Storage>>Tap on Clear data >>Tap on Clear cache>>Restart your device>>Try sending a text message.
In case the issue still occurs. Please register your concern in Samsung Members Application (Open Samsung Members Application > Support> Tap on error report > Type your query > Send).
