Stolen iPhone - Red lock icon next to my iPhone on Apple Watch Find Devices

My iPhone was recently stolen. I turned on Lost Mode, but I am not sure whether it is activated. What does the Red lock icon next to my iPhone on Find Devices app on Apple Watch mean? Did I successfully activate Lost mode? Because on Find my iPhone it says that the action is pending because iPhone is offline. Also the Find My iPhone feature on PC browser says thah iPhone is offline and therefore no location is displayed, but apple watch got a new location of my stolen iPhone!!