I have been having the same issue for weeks now, which is quite frustrating: I had gotten a windows 10 phone and previously had SMS messages able to be sent and received via the action center - it isn't working anymore. I checked all of my notification settings and everything appears to be in order but SMS notifications are still not showing in the action center. I enabled a workaround using Skype Preview as my default messaging service and that works fine and is similar in functionality. However, I'd really rather not use Skype at all; certainly not as my default messaging service on my phone. Basically, I want to be able to text on my phone when not on my PC and manage (send and receive) my text messages on my phone via my PC while I'm working on my PC. Picking up and unlocking my phone repeatedly while working on my PC can be quite annoying while working a task. I don't want to have to utilize a various apps to get this done. The way the phone and action center worked in, I want to say August, was perfect. Then sometime in late September or October this functionality ceased. I would really like to see it return to the way it was, it's a feature I had been waiting for on a Windows device that Androids had used years earlier.