Forerunner 55 does not syncs with garmin connect app ios

I use a Forerunner 55. For a week now, the data from my watch no longer syncs with the Garmin Connect app: sleep, body battery are missing. All other data is only visible a day later and is not accurate. I have already deleted the app, removed my watch from the app and from Bluetooth, synced more often. What else can I do?