I am using Ubuntu 18.04 VPS, and installed Codiad on /var/www/codiad and updated the permissions for relevant files and folders as specified here.
I did not update anything on the Codiad config.php file, and i have used Symlink as described here to access project files outside Codiad's workspace. My project files are located at /var/www/projects/yellowbin.
I have added my user into the www-data group and set owner to www-data from www/projects/yellowbin with 775 permissions and still could not work. I have reverted the setting as it could not work.
Here is the project explorer in Codiad.
Here is the permission set on the server, from www directory to the project files.