Huawei applies a default restriction policy for background processes. This prevents Health Sync from processing the sync in the background. You can fix this as follows:

1. Open your phone settings menu
2. Open the Battery menu
3. Make sure that “Performance mode”, “Power saving mode” and “Ultra power saving mode” are all three disabled
4. Then select the App Launch menu
5. You get a list of all your apps. Search for Health Sync and select the button: set it to “manage manually” and accept all three background options.