iPhone 6s, IOS 10.2... and all of a sudden I press home button and speak into the phone, " call James Brown"... she says calling James Brown, and then says she can't make the call.
I've read about this on forums with no solution found.
Have you tried some troubleshooting steps? Disabled and re-enabled Siri? Restarted the phone? Took out and placed back the SIM card? Reset network settings? Perhaps reset all settings?
so it works in the car but not in the office? try turning off wi-fi for a minute in the office and try it again next time you're there with wi-fi off — i'd be curious to see if it works.