I have a DSS button (ext. 104) blinking on all phones. The extension (104) is NOT in DND. It is a normal idle display on ext. 104. Intercom calls to 104 go through as normal. Any ideas how to clear this?

An extension that is call forwarded will also cause the dss key to blink.

Does it flash all the time or only when a call is ringing to it? It's obviously not all-call forwarded since calls make it through, but could another form of forwarding be active, like no answer?