Just got the S6 Edge last night. Got home, did the update. Wake up this AM... NO SERVICE!! Took the SIM card out, restarted, not in airplane mode... still nothing. Help!!! We have T-Mobile.
Hello friend, the problem is just ... go to Settings> Mobile networks> Network mode > And try to change the selection option , eg GSM only .. and see if the reset signal is good. Mime me what happened with my s6 edge after the upgrade and I resolved by setting the option GSM\HSPA(auto connect), now I have 4G network without problems.
Just bought my edge yesterday, also on TMobile. I haven't received any update yet, I tried to pull OTA fresh out of the box but I didn't see anything...
However, I have noticed that this phone has a much stronger LTE signal in my house than my Note 4 did.... I'm very happy about that.
Personally, I'd say call/ go to T-Mobile as soon as you can! Good luck!
Had this happen on another phone. While I was trying different things with it to get a signal I put it in airplane mode for a couple of minutes and switched that off. The phone gave me a message "preparing sim card" and then the signal returned. You might try that before having to go back to the phone store.