Short post about OroCRM 1.10 on CentOS 7.2. The original install instructions are good. If you have the OroCRM behind a reverse proxy which is not HTTPS, then you need to configure trusted proxy otherwise, there will be errors.
trusted_proxies: [192.0.0.1, 10.0.0.0/8, cloud_flare_ip ]
Also, change sending address in System -> Email Configuration if it has taken localdomain or something not resolvable from outside. Otherwise outgoing mails may be blocked.