LAMP. When the owner /var/www/site/ -> www-data and group USER1, result: er

LAMP.

• case 1:
  When the owner of /var/www/site/ -> www-data and group USER1, result: files upload on server from index.php BUT i CAN’T edit from sftp the files on server from USER1. (permission denied)

• case 2:
  When the owner /var/www/site/ USER1 and group www-data, result: error when files uploads on server from index.php BUT i can edit from sftp the files on server from USER1.