Connection error with Android

Good afternoon,
I'm trying to connect to my OwnCloud via the Android OwnCloud App.
The app is connected to the server (connection has been established).
When I fill in my username and password, I get the error: "wrong username or password".
However when I log in via the browser, I get access.
Owncloud version is 9.1.4

Is this a known issue?
Is there a variable I should fill in?

Thank you.
Kind regards,

Suz

You most likely have a broken WebDAV interface / setup at the server (The client is using WebDAV and Basic Authentication where the Browser is using another session mechanism).

The following FAQ [1] contains all known information and workarounds how to fix the webserver config which should solve such issues.

[1]

Thank you for your swift response. I'll check the webdav.