After configuring WordPress in a VPS it is common to have a permission error in which FTP credentials are requested to install plugins.
What is a solution to solve the FTP credentials problem?
On a web server with Nginx this is easily solved by adding the following line in your wp-config.php file:
If you use Ubuntu to fix the permissions on the WordPress installation folder run the following command:
#change “root_directory_wordpress” with a name of the folder that WordPress was installed.
$ sudo chown -R www-data:www-data
With this solution probably you will solve the problem if you can know more about permission on WordPress folders and files, You can click here and read this article on the WordPress Codex that talks about this.
If you know something more that I don’t mention on this post, please leave in comments and I’ll add in this post.