I have an SPA504G running firmware version 7.4.6. The LED at the top of the phone that is supposed to light when the phone rings and when there is a voicemail message waiting never lights. When I dial the phone the line button turns Red (so maybe the documentation that says the MWI LED should blink is wrong).
When I have a voicemail waiting, the llittle evenelope icon appears on the LED screen next to the extension, but the MWI LED does not light up.
Any suggestions as to where I should look?