Why won't sms messages send to certain numbers?

[AC Question]

After I updated my Nexus 5 to Android 6.0, I can't send texts to radio station text lines. My network connection is fine, I can send sms and hangouts to any contacts. I tried adding the station number to my contacts but that hadn't worked either. Before the system update I could uninstall the hangouts update and it would work properly. Now I'm stuck with an app that doesn't work properly.