Hey there,
since the new MacOS Versions SeaDrive has a lot of sync error unfortunately. Today we encountered another bug, which did not throw an error:
Certain Files in a Folder called “Links” are not synced to the client.
When Adding a New Folder in “Links”, it get synced to the SeaFile Server (checked via Web)
When trying to download all files of the parent folder of “Links” by clicking on the Cloud-Icon in the Finder I’ll get the following error: NSFileProviderErrorDomain Code=-2005
No error is shown when checking via the seaDrive Icon in the MacOS-Bar on the top right
If it fails, you might try this: Quit SeaDrive, completely uninstall it (using a program like AppCleaner or App Cleaner & Unistaller), reboot, install a fresh copy of SeaDrive Client 3.0.11 and see if you can login and sync all your Libraries.
In my experience it can be a bit tweaky and tedious but it will fix. Expect to reboot several times.
You can open Finder and click the SeaDrive entry in the left pane. Sometime you have to access the SeaDrive cache folder to activate the system extension.