You can try delete data on your iCloud account (if using CloudSync) by following these instructions:
- update the app to the latest version on all your devices. It should be v4.1.5 on iPhone and iPad, and v1.4.5 on the Mac
- turn off CloudSync sync on all devices, if it’s enabled
- On iOS, delete the previous CloudSync data -> from the More page, select Sync Settings
- press-and-hold on the CloudSync option, and then select the “Delete CloudSync Container” option to clear out the CloudSync data.