403 forbidden to PUT - status blacklisted

Steps to reproduce

  1. upload directory with file to windowd Owncloud directory
    2.start sync

Expected behaviour

files shall be uploaded to server

Actual behaviour

getting 403 forbidden to PUT - status blacklisted error

Server configuration

Operating system:
Debian 11

Web server:
apache_nginx

Database:

PHP version:
7.4

ownCloud version: (see ownCloud admin page)
10.11.0.6

Updated from an older ownCloud or fresh install:
fresh install

Where did you install ownCloud from:
Owncloud website

Signing status (ownCloud 9.0 and above):

Login as admin user into your ownCloud and access 
http://example.com/index.php/settings/integrity/failed 
paste the results into https://gist.github.com/ and puth the link here.

No errors have been found.

The content of config/config.php:

Log in to the web-UI with an administrator account and click on
'admin' -> 'Generate Config Report' -> 'Download ownCloud config report'
This report includes the config.php settings, the list of activated apps
and other details in a well sanitized form.