EnpassPortable 5.3.0 (59) on OSX 10.11.6 and also unable to get WebDAV sync to work. Android (paid) version syncs without any issues, but OSX version errors out with "Error code: -117". WebDAV server is nginx and the error message when attempting sync from OSX client is:
2016/11/19 21:09:41 [error] 12757#12757: *811 MKCOL can create a collection only, client: 192.168.100.10, server: , request: "MKCOL /sync/Enpass HTTP/1.1", host: "server.example.com"