If you are experiencing WebDAV issues with database sync and you are using Synology NAS, there are a few steps that you can try and fix the problem:
- In Synology, check the "Intermediate Compatibility" option. This could be in either of these locations:
- System Settings > Security > Extended
- Control Panel > Security > Advanced
- In the pop-up window, in the WebDAV Server line, select the "Old compatibility" option.
- After that, just hit "OK" and "Save" and your issue should be resolved.
There are more helpful tips and tricks available here:
https://strongboxsafe.com/updates/syncing-with-synology-nas/
NOTE: Synology DS File doesn't work very well with with iOS "Files", so we always recommend that you use WebDAV.