Check the status line under Sync now: it reports what the last automatic pass did. Most sync problems are one of five things, and the line tells you which.

1. The automatic pass is failing

Pressing Sync now can succeed all week while the background pass fails every run, so a green manual result means nothing on its own. Read the line under the button. If it names an error, that is the fault; if it says the last pass was long ago, the app has not been given a chance to run in the background — open it, leave it, and check again.

2. Different folders

Both devices must point at the same address and the same folder. A trailing folder name that differs by one letter makes two ledgers that never meet. Compare Settings › Sync on each device, or export the settings from one and import it on the other.

3. Credentials

A changed WebDAV password, an expired Google sign-in, or a token revoked on the server. Sign in again or re-enter the password; the status line will say “unauthorized” or similar.

4. It synced, but the other device has not pulled yet

Sync runs on a cycle, on open, and on close. If you wrote on the Boox and the iPad shows nothing, run Sync now on the iPad. Reading positions push after five quiet seconds; listening positions push on pause and stop, not while playing.

5. A stroke came back after you erased it

This is the merge’s one known limit: an erase made in a way that left no record can be re-added by a device that still had the stroke. It is rare and deliberate; a returning stroke is a smaller harm than a lost page. Erase it again on the device that shows it, and it stays gone. See How sync works.

What sync never does

• It never discards one device’s strokes in favor of the other’s. Both sets are kept.
• It never rewrites a day into a format only the app can read.
• It never uploads a half-written file as if it were whole.

Checking the server by hand

Browse the WebDAV folder or the Drive folder. You should see calendar/2026/09/day-2026-09-03-v2.json and its neighbours, plus a few small files at the root. If a day is there but not on the device, the device has not pulled; if it is not there, the device has not pushed.

Widgets out of date

Widgets show what the app last published, not the server. Open the app once and they refresh on the next cycle.

Still stuck

Note the status line’s exact words, the device, and the version from Settings › About, and see Report a bug.