Unable to change owner

I’m trying to remove redis from my wpredis site. When I run the command: sudo ee site update exemple.com --wp

it gives me the following error: Running pre-update checks, please wait… Backup location : /var/www/example.com/backup/07Apr2017031604 Backing up database [Done] Setting up NGINX configuration [Done] Setting up webroot [Done] Setting plugin nginx-helper, please wait… Uninstalling plugin redis-cache, please wait… Reload : nginx [OK] Unable to change owner : /var/www/example.com

The site info still shows it as wpredis: Nginx configuration wp wpredis (enabled) PHP Version 5.6 HHVM disabled SSL disabled

The output from sudo nginx -t is: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful

I would really appreciate any help.

Thank you,

Alexandre.