Probably means the SSL/A Records of this website are missing something/not written in a way that browser understands.
And yes, I've only seen that notification pop up when on Android Chrome. The web admin probably needs to research android chrome a bit to see if there's anything specifically needed for https:// websites.
LvL 100s: Beorning, Burglar, Captain, Champ, Guardian, Hunter, Lore-Master, Minstrel, Rune-Keeper
LvL 85: Warden, Minstrel
All my forum posts are my opinions and may not even be that. Also On Twitter: @leixicon