I received a watch firmware update yesterday morning. An hour later my numbersync disabled itself. Have not been able to get it enabled since. Keep getting either the service is unavailable error, or the RESCOM0111 error. I have fought AT&T's numbersync service for 5 years now. Longest it's ever stayed on is a month. It randomly turns itself off, then it's a nightmare to get it working again.
I'm going to try resetting the watch again, and see if that works, and I'll post an update afterwards.
Factory resetting the watch did not fix it. Same issue remains, error RESCOM0111 after inputting the pin/code from the watch. Just a little detail. I am using a Galaxy Watch 3 with a Galaxy Note 10+ both on AT&T.