Message string messed up when sending email with Codeigniter email class
I had the same issue and "@Alix Axel" helped to resolve it.
See this post: CodeIgniter SMTP email message - characters replaced with equal signs
It covers what configurations you need.
Try changing the charset to utf-8.
$config['protocol'] = 'mail';$config['charset'] = 'utf-8';$config['wordwrap'] = FALSE;$config['mailtype']= "html";