We have NAV 2013 R2 configured to work with Zetadocs Express using a Zetadocs Archive (instead of SharePoint).
In Zetadocs General Settings, Archiving is set to Zetadocs Archive and the Service Address is http://10.1.60.44/ZetadocsArchive. Clicking the 'Open in browser' icon next to the address opens up a web page which starts with "ArchiveService Service. You have created a service.".
On the server hosting the service (a different server from the NAV service tier) there's a share called Zetadocs Archive. The service is running under the default 'Local System' account (trying to change it to another account results in a 'semaphore already exists' error and the service won't start). The permissions on the shared directory gives full control to the SYSTEM and domain administrator account and read-only access to Authenticated Users. When logged in as the domain administrator I can connect to the share from another machine using Windows Explorer at \\10.1.60.44\Zetadocs Archive and add files successfully.
The Zetadocs Express FactBox has been added to various pages including the Sales Order using the Zetadocs Express Page Modifier tool. Opening the Sales Order page gives the Documents FactBox which says 'Drag Files Here'. Dragging a file there results in the file being added to the archive folder (along with a 2nd file called 94e7514d-e82c-4ff6-8d80-c3836563208c.zdx) but the factbox then shows an error saying "Failed to search for documents. To solve the problem, please contact your administrator". Closing the order and reopening it removes the error and shows the file attachment. Clicking the attachment then results in an error saying "Failed to download document: 94e7514d-e82c-4ff6-8d80-c3836563208c. To solve the problem, please contact your administrator". Opening either file (the attachment or the .zdx file) directly from the network share \\10.1.60.44\Zetadocs Archive works fine.
On other pages (such as the Item, again modified with the interface tool), dragging a file to the documents factbox gives an error saying "Failed to archive document. To solve the problem, please contact your administrator" and the file is not added to the share.
I've tried turning the firewall off on both machines and that has no effect, I've tried installing the Zetadocs Archive on a different server and get the same result, and I've tried from different NAV databases with the same results each time. Any ideas what could be wrong?