I hadn't been able to use Siri for hours so I did the following and now it works perfectly. Reboots didn't work and turning Siri off and on didn't work either. If yours isn't working, try this and let me know if it works. Settings>General>Siri Turn it off then go to Settings>General>Reset> Reset Network Settings and Confirm. It will take a moment while it resets. Now turn Siri back on and see if she works.