Experiencing issues with Siri in High Sierra.

Hi all,

I recently updated my computer to macOS High Sierra. It's been running fine, but I have been experiencing some issues wiht Siri. I generally use the Siri icon on the top right of the screen to acces Siri. When I press the button, the little Siri window pops up and it makes the apropriate "duh-ding" noise, but the icon that indicates that Siri is listening does not move, and it does not respond to any voice prompts or to clicking. I close the window with the x and that's all. Sometimes it will make the "duh-ding" noise a little later but after the window is closed. Basically the same thing happens if I use the lauchpad icon. What is causing this problem? Is there anything I can do to fix it?

Thanks in advance!

I restarted the computer and Siri now works. It would be great to know what causes the issue, but I guess this works too.