Some programs or scripts may require you to give files or folders specific permissions in order for them to work.
To do this with FileZilla simply right-click the remote file or folder and choose the “file permissions” option. Set the numerical permissions specified by the program writers and click “OK”
If you use a different FTP program consult the help section of your software.
Or you can change file and folder permissions by using the file manager found in your hosting Cpanel