"Home" Button registers but does not take action

[Machinus]

I have haptic feedback enabled and I can feel the button press, but it does not do anything. How can I fix this?

 

[Benton]

Have you tried a reboot (volume down & power button pressed at same time)?

 

[Machinus]

Yes, I did reboot my phone, for other reasons. This button stopped working overnight, and I am not sure why.