Send mail from local host in codeigniter on cloudflare hosting

Recently I have added my site in my hosting to Cloudflare. Before adding to cloudflare, the email was sent from localhost when I put my email and credentials in my codeigniter web apps but after adding to cloudflare, the mail does not send. There was problem with filezilla client as well and I added the ip address in my FTP instead of domain name and it worked now. What setting shall I use in mail config in codeigniter in localhost?

Hostnames used for mail should be set to :grey:.