I can receive text from one individual but can't send text to him.

[Android Central Question]

I can receive text from one individual but can't send a text to him. I get a triangle icon with a explanation point in gray. I'm using a HTC Android phone. How can I fix this problem?

 

[B. Diddy]

Welcome to Android Central! Are you sending simple texts (SMS) or MMS (i.e., photo texts)?