I have a fresh install of Nextcloud 12 on Ubuntu 16.04. I can access nextcloud thru the browser. I downloaded the windows app and when I try to connect I get this error.
If you use 2nd factor authentication, you need to set an app password for the client first. If that is not the case, a quick look in the server logfiles could perhaps help. Other native webdav clients (cyberduck, winscp) work?
somehow it started working…