Free Message: message Blocking active is turn on. ( if you have T mobile )

I found that on iPhone I could not sent a text because when I did I got the Message above. how to solve if you have the T mobile app on your Phone, then open the app, then go to setting in the app, find your phone number click on that then you will see Blocking phone call and Message then turn it to off then you will be able to send and receive text messages thanks DJC