What phone do you have? Google Pixel 2
What plan are you on? My choice Talk and Text
Does your plan include data, or just talk & text? just talk and text
My daughter’s phone has been having issues with sending/receiving texts periodically. I’ve had the same issue with my phone (moto g4) but not nearly as often and it hasn’t happened on my phone for over a month. Anyway, on my daughter’s phone when she isn’t able to send/receive texts, she’ll turn her mobile data off and back on and that sometimes takes care of it (that’s what fixed it on my phone as well). Sometimes when this trick doesn’t work on her pixel, she turns her phone off and back on. This sometimes fixes the issues as well. If not, she just has to wait and it will eventually start working again.