After installing version 1.4.15-x64 on my Windows 10 PC and and unlocking my vault, I get an error message that it is not possible to connect to the given drive (when changing the drive letter - same error message). Using WebDav instead of Dokany brings the same error message.
Deinstalling the new version and reinstalling the 1.4.13-x64 version helps. No more error message, everything works fine!
So to me it looks like there’s a bug in the newest version.
Try to remove Vault from cryptomator application ( Via - ) and ADD ( via +, open Existing Vault) again.
This is how I sometimes notice this type of issues -> not related to this version …