Support

"No readings found"

Nine times out of ten the Health permission got skipped. On the iPhone go to Settings, Privacy & Security, Health, Halo and hit Turn On All, then come back and tap Read again. If you have no watch and a new phone there may honestly be nothing in Health yet. There's a button to look at example readings in the meantime.

Cancelling or restoring Halo Plus

To cancel: iPhone Settings, your name at the top, Subscriptions, Halo. You keep Plus until the period you paid for runs out, and a free week that's cancelled before it ends costs nothing. New phone or reinstalled? Tap Restore on the Halo Plus screen, signed in with the same Apple Account.

"Still learning"

New watch? It needs roughly three weeks of you wearing it to bed. Nothing to press.

"No night readings" / "No recent nights"

The steady-or-shifted call is made from what the watch records while you sleep. If it spends the night on the charger, Halo has nothing to judge and says so instead of guessing. Daytime stuff like steps keeps working.

Why don't I have wrist temperature (or blood oxygen)?

Depends on the watch model. Also any measure needs about 20 days of readings before it gets a usual range, so a brand new one sits under "Not judged" for a while.

No Halo on my watch

iPhone, Watch app, scroll down to Available Apps, Install.

The ring disappeared from my Lock Screen

That's iOS. It removes these after eight hours and I can't extend it. Open Halo and it comes back.