IPhone 5s all of a sudden is not receiving texts from other IPhones

[iMore Question]

This appears to be an IPhone to IPhone thing. I am receiving from other types of phones. This just started a few days ago. My friends and family are receiving my texts but I don't receive their answers. Is there a setting issue I'm not aware of?

 

[kch50428]

https://support.apple.com/en-us/HT204065