I've rebooted my phone and am in an area where cell service shouldn't be a problem and only intermittently get texts while in the same location. I briefly thought problem was fixed after a call to Fido, but is clearly still an issue as I'm missing texts daily. Who knows how many. The missing texts never arrive either.
I switched to the stock Samsung app on my phone to see if it would fix the problem. It says it's the most recent version but it isn't that one. I'd rather go back to my Messages app I've been using without any problem for the first year that I owned this phone and the past several before that.
Just a heads up, @Lilysmart, I moved your posts to a new thread since we're discussing a different device and the previous thread was related to the LG G5 exclusively.
Now, which model of Samsung device are you using specifically and which software version are you running on the device?