My 6T is also having this issue. After some time, I'm not able to receive/make calls receive/send SMS even mobile data remains enabled and teleports notifications coming in.
The reboot fixes, but after it repeats. I'm using the 2G/3G/4G option. Some other people are also having this issue. I've to send a sms myself to check if at that moment I'm able to receive calls. Since last RC update this became an everyday problem.