What to set the rights to the folder?

Question

linux

Hello!
On the Ubuntu 18 + Nginx server, there is a folder with a site /var/www/site.rufor which the owner is set like this:
$ sudo chown -R www-data: /var/www/site.ru
And the FTP client “vsftpd” is also installed, with a user folder /home/customuser/ftp/datafor which the owner is set like this: Accordingly, so that you can interact with site files via FTP (change, delete etc.), the sites folder is mounted to the FTP user folder. Like this:
$ sudo chown $USER:$USER /home/customuser/ftp/data

$ sudo mount --bind /var/www /home/customuser/ftp/data

The site admin panel works fine (uploads and deletes files without problems), but when connecting via FTP and trying to upload something to a folder, an error occurs (does not allow uploading or deleting files).
How to properly set folder owners under such a system?
PS Rights everywhere 755 and 644.
Thank you!

Answer 1

Most likely vsftpd and the webserver are running under different users.
You can add these different users to the same group

Answer 2

For me, it's easier to get a user under the site. Throw the site itself into the user's hamster and connect via sFTP using the user's login and password.