Android app doesn't work with TransIP Stack Storage

When using the Android app for the first time, the server address needs to be entered. If I enter the webdav address of Trans IP Stack Storage, the app says: Wrong username + password. There is no possibility to enter a username + password.

I would expect some fields to enter an username + password.

Android version: latest

Device model: Samsung S9

Stock or customized system: Stock

ownCloud app version: latest

ownCloud server version: none

@BVNL Is Trans IP based on an older ownCloud version? Starting with oC Android 2.9.3, minimum requirement is a oC 9.1 server version, due to a new WebDAV endpoint.