Learn how to handle file permission issues in YOOtheme Pro.
There are two ways of accessing files when working with WordPress: either directly via your web server or through an FTP client. Different files and directories have permissions specifying who can read, write or access them. Sometimes the permission settings of your web server and your FTP client can collide, so that when trying to install a theme or plugin, you are suddenly confronted with an error message, or you may not be able to save theme settings.
To resolve these issues, you need to change the permissions of the affected files or directories. We recommend
755 for directories and
644 for files.
Take a look at the WordPress documentation for more information.
Here is a short guide on how to change file permissions with an FTP client.
See also the official WordPress guide.