Spezial characters in Wiki

Hello everybody,

since the first use of XWiki with German interface I have problems with the use of special characters in the title, attachments and images we upload or want to include in our sites

These cannot be displayed or show with error messages.

After renaming, pages are no longer accessible or the content has disappeared.

Is there someone here who could solve this problem?

Maybe someone here can help me

Thanks for your help in advance

Using XWiki 11.10.2