Cannot initiate text messages to one contact Galaxy S6

[Android Central Question]

My wife's S6 on AT&T. She cannot initiate a text to her niece's Android phone (also on AT&T). She sends them, but her niece doesn't get them. If she replies to a text her niece has sent, that goes through. Phone calls go through normally, too. Her niece recently changed phone numbers.

I have an iPhone on AT&T and am able to text her flawlessly.

We have tried deleting and recreating the contact.

Any ideas welcome.

 

[A Bochur]

after sending message, check near the name in the messaging app, it should say the phone number. check if it's the correct one