PHP Elfinder file manager. Does not allow you to download, edit and archive files. Why?

Question

PHP

Hello everyone, I installed the Elfinder file manager on the site, an excellent manager, the set of functionality suits, but there were difficulties. I put Elfinder myself along the path home/user/site.ru/www/filemgr/. (The site itself lies along the path home/user/site.ru/www/ ). The file manager works, shows folders and files, moves freely to the directory above, to the folder with the site itself, BUT does not allow you to perform any actions in this folder, neither upload there, nor delete, nor archive ((
I can’t understand why ... maybe in the config you need to add something or fix it?
And yet, in your folder (home/user/site.ru/www/filemgr/) The file manager allows you to do all the actions with folders and files.I
ask for advice from those who are familiar with this file manager

Answer 1

I figured out that the group had no rights to the www folder. Now loading, etc. work, but now another question has arisen: Why does this file manager only allow editing .txt files? for some reason .php opens, but does not save