Can’t send a text to certain numbers

[Joetheauthor]

I have an Alcatel idol 3, one touch phone on the Cricket network. When I try to send a text to a number, sometimes I get a message saying “Error Invalid Number. Please re-send using a valid 10 digit mobile number or valid short code.” I have sent texts to the number in question before. I also get this message when I try to text my daughter-in-law.
Help!!