user/group is being set to www-data not to virtual server's user/group


i am a little confused.

After upgrading to 3.99 i needed to setup an existing domain one more time, because this was easier, than removing all databases, Emailadresses etc. to rebuild the website and everything else for the domain.

Now i seem to have a problem. After deletion of the virtual server and creation of the same domain as a virtual server, it looks like the Application, Joomla as a matter of fact, creates new files with www-data as user:group. Therefore some files and folders cannot be read from other plugins, which confuses the system. The only chance i have is, changing the owner/group, whenever there are new files being uploaded, whether they are plugins or media or or or.

How can i fix that, so that Joomla is able to use the virtual domain user’s user and group for new files and folders?