Guessing: see if you can successfully send messages to someone else. The phone number you are trying to TXT may be blocking you. You could also try calling that number... If that is not the case, I might try shutting down the phone, pulling the SIM card, waiting a few minutes, re-inserting the SIM card and powering back up. If that doesn't work, I would try chatting or calling VZW customer support.
angels63, I want to make sure you are able to send text messages without any issues. How long have you been getting this message when you try to send a text message. Are you getting it when you try to send one to a certian person or is it with many contacts? Also, are you using the default text message application or a 3rd party application from the Play Store? Please keep us posted.
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