It sounds like the icon is there, it is just not displaying signs of activity noted by the blue or red arrows and further confirmed in the traffic logs. This is not an exact issue I have seen before on the support forums before.

I would like to ask if there has been any changes to your system at the time of this change?

Microsoft patches? Any software or hardware changes?

Can you find any errors with Dr.Watson or Eventviewer (depending on version of Windows)?

Does the SPF debug log offer any clues?