Sync-Plugin stopped working

I use DEVONthink Pro Office (at the moment 2.4.3) and since weeks I use the new sync-plugn, it worked without any problems. But now it stopped working - for me without any reason.

The plugin and the pref.pane are in the folder

~/Library/Application Support/DEVONthink Pro 2/Plugins/

and the “Sync-section” is shown in the preferences of DEVONthink. But it is not possible to klick an this section, it seems to be inactive

I tried to reinstall the plugin but nothings changes. What has happened?

See Sync pane broken


DEVONthink had changed to 64-bit-mode (but I don’t know, what caused the change)