same problem for me on my ipad pro and iphone, both on ios 11.2.1 apps update -> same problem for an immediate solution, i delete the owncloud client and reunstall no problem all is ok but I have to resynchronise lically all my "off line" folders
Please try to delete the app using Settings -> iPhone Storage -> ownCloud -> Delete App. Reinstall it from the AppStore. This workaround fix this problem. We working on a fixed release.
I have the latest version 3.7.2 installed, when I open the app I only get the window to enter the WEBDAV URL but no user/password field. When I enter the URL and press Connect there is an error message "Der Benutzer oder das Passwort sind falsch".