The short answer
You taught your team what to share by how you reacted. Every time you rewarded agreement and cooled toward bad news, you sent a clear signal. The information stopped coming because the cost of honesty got too high. You can reverse this, but you have to go first.
You built a mirror when you needed a window. Research on team culture is consistent on one thing: the norms inside a team are almost always set from the top, quietly, through reaction — not through stated values. Every time you lit up at good news and went quiet at a hard truth, people took notes. They were not being dishonest. They were being rational. The culture that formed is the one you reinforced, one interaction at a time.
Marcus Aurelius writes about the profession of being good — and the job of a leader is close to that. Being good here means actively making it safe to tell you the truth. Right now, the charitable act your team needs from you is not a speech about open feedback. It is a visible change in how you receive hard news the next time it arrives. That moment is the real signal.
This week, find one person on your team and ask them directly: 'What's something I should know that you haven't told me?' Then listen without defending, without fixing, and without rewarding the answer so enthusiastically that it feels fake. Just thank them plainly and act on one thing they say. Do that with one person. Word will travel faster than any all-hands message.