Syncing

When nothing arrives

Work down the list. Most of the time it is one of the first three lines.

1. Are both devices signed in to the same Apple ID?
2. Is iCloud Drive enabled on both?
3. Is Low Power Mode on on the iPhone? It delays background transfers.
4. Does Settings, General show a last sync error?
5. Is your iCloud storage full? Large image attachments count against it.

If all of that is fine

Quit both apps completely and start them again. If that changes nothing, send us the error message from the settings and we will look into it: reinke.support@gmail.com.